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2026-01-15perf/x86/intel: Add support for PEBS memory auxiliary info field in DMRDapeng Mi
With the introduction of the OMR feature, the PEBS memory auxiliary info field for load and store latency events has been restructured for DMR. The memory auxiliary info field's bit[8] indicates whether a L2 cache miss occurred for a memory load or store instruction. If bit[8] is 0, it signifies no L2 cache miss, and bits[7:0] specify the exact cache data source (up to the L2 cache level). If bit[8] is 1, bits[7:0] represent the OMR encoding, indicating the specific L3 cache or memory region involved in the memory access. A significant enhancement is OMR encoding provides up to 8 fine-grained memory regions besides the cache region. A significant enhancement for OMR encoding is the ability to provide up to 8 fine-grained memory regions in addition to the cache region, offering more detailed insights into memory access regions. For detailed information on the memory auxiliary info encoding, please refer to section 16.2 "PEBS LOAD LATENCY AND STORE LATENCY FACILITY" in the ISE documentation. This patch ensures that the PEBS memory auxiliary info field is correctly interpreted and utilized in DMR. Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20260114011750.350569-3-dapeng1.mi@linux.intel.com
2026-01-15perf/x86/intel: Support the 4 new OMR MSRs introduced in DMR and NVLDapeng Mi
Diamond Rapids (DMR) and Nova Lake (NVL) introduce an enhanced Off-Module Response (OMR) facility, replacing the Off-Core Response (OCR) Performance Monitoring of previous processors. Legacy microarchitectures used the OCR facility to evaluate off-core and multi-core off-module transactions. The newly named OMR facility improves OCR capabilities for scalable coverage of new memory systems in multi-core module systems. Similar to OCR, 4 additional off-module configuration MSRs (OFFMODULE_RSP_0 to OFFMODULE_RSP_3) are introduced to specify attributes of off-module transactions. When multiple identical OMR events are created, they need to occupy the same OFFMODULE_RSP_x MSR. To ensure these multiple identical OMR events can work simultaneously, the intel_alt_er() and intel_fixup_er() helpers are enhanced to rotate these OMR events across different OFFMODULE_RSP_* MSRs, similar to previous OCR events. For more details about OMR, please refer to section 16.1 "OFF-MODULE RESPONSE (OMR) FACILITY" in ISE documentation. Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20260114011750.350569-2-dapeng1.mi@linux.intel.com
2026-01-15perf/core: Fix slow perf_event_task_exit() with LBR callstacksNamhyung Kim
I got a report that a task is stuck in perf_event_exit_task() waiting for global_ctx_data_rwsem. On large systems with lots threads, it'd have performance issues when it grabs the lock to iterate all threads in the system to allocate the context data. And it'd block task exit path which is problematic especially under memory pressure. perf_event_open perf_event_alloc attach_perf_ctx_data attach_global_ctx_data percpu_down_write (global_ctx_data_rwsem) for_each_process_thread alloc_task_ctx_data do_exit perf_event_exit_task percpu_down_read (global_ctx_data_rwsem) It should not hold the global_ctx_data_rwsem on the exit path. Let's skip allocation for exiting tasks and free the data carefully. Reported-by: Rosalie Fang <rosaliefang@google.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20260112165157.1919624-1-namhyung@kernel.org
2026-01-15rust: xarray: add __rust_helper to helpersAlice Ryhl
This is needed to inline these helpers into Rust code. Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Acked-by: Tamir Duberstein <tamird@gmail.com> Link: https://lore.kernel.org/r/20260105-define-rust-helper-v2-27-51da5f454a67@google.com Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
2026-01-15net: can: j1939: j1939_xtp_rx_rts_session_active(): deactivate session upon ↵Tetsuo Handa
receiving the second rts Since j1939_session_deactivate_activate_next() in j1939_tp_rxtimer() is called only when the timer is enabled, we need to call j1939_session_deactivate_activate_next() if we cancelled the timer. Otherwise, refcount for j1939_session leaks, which will later appear as | unregister_netdevice: waiting for vcan0 to become free. Usage count = 2. problem. Reported-by: syzbot <syzbot+881d65229ca4f9ae8c84@syzkaller.appspotmail.com> Closes: https://syzkaller.appspot.com/bug?extid=881d65229ca4f9ae8c84 Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Tested-by: Oleksij Rempel <o.rempel@pengutronix.de> Acked-by: Oleksij Rempel <o.rempel@pengutronix.de> Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Link: https://patch.msgid.link/b1212653-8fa1-44e1-be9d-12f950fb3a07@I-love.SAKURA.ne.jp Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2026-01-15Merge patch series "can: raw: better approach to instantly reject ↵Marc Kleine-Budde
unsupported CAN frames" Oliver Hartkopp <socketcan@hartkopp.net> says: This series reverts commit 1a620a723853 ("can: raw: instantly reject unsupported CAN frames"). and its follow-up fixes for the introduced dependency issues. commit 1a620a723853 ("can: raw: instantly reject unsupported CAN frames") commit cb2dc6d2869a ("can: Kconfig: select CAN driver infrastructure by default") commit 6abd4577bccc ("can: fix build dependency") commit 5a5aff6338c0 ("can: fix build dependency") The reverted patch was accessing CAN device internal data structures from the network layer because it needs to know about the CAN protocol capabilities of the CAN devices. This data access caused build problems between the CAN network and the CAN driver layer which introduced unwanted Kconfig dependencies and fixes. The patches 2 & 3 implement a better approach which makes use of the CAN specific ml_priv data which is accessible from both sides. With this change the CAN network layer can check the required features and the decoupling of the driver layer and network layer is restored. Link: https://patch.msgid.link/20260109144135.8495-1-socketcan@hartkopp.net [mkl: give series a more descriptive name] [mkl: properly format reverted patch commitish] Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2026-01-15can: raw: instantly reject disabled CAN framesOliver Hartkopp
For real CAN interfaces the CAN_CTRLMODE_FD and CAN_CTRLMODE_XL control modes indicate whether an interface can handle those CAN FD/XL frames. In the case a CAN XL interface is configured in CANXL-only mode with disabled error-signalling neither CAN CC nor CAN FD frames can be sent. The checks are now performed on CAN_RAW sockets to give an instant feedback to the user when writing unsupported CAN frames to the interface or when the CAN interface is in read-only mode. Fixes: 1a620a723853 ("can: raw: instantly reject unsupported CAN frames") Cc: Marc Kleine-Budde <mkl@pengutronix.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Vincent Mailhol <mailhol@kernel.org> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Link: https://patch.msgid.link/20260109144135.8495-4-socketcan@hartkopp.net [mkl: fix dev reference leak] Link: https://lore.kernel.org/all/0636c732-2e71-4633-8005-dfa85e1da445@hartkopp.net Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2026-01-15can: propagate CAN device capabilities via ml_privOliver Hartkopp
Commit 1a620a723853 ("can: raw: instantly reject unsupported CAN frames") caused a sequence of dependency and linker fixes. Instead of accessing CAN device internal data structures which caused the dependency problems this patch introduces capability information into the CAN specific ml_priv data which is accessible from both sides. With this change the CAN network layer can check the required features and the decoupling of the driver layer and network layer is restored. Fixes: 1a620a723853 ("can: raw: instantly reject unsupported CAN frames") Cc: Marc Kleine-Budde <mkl@pengutronix.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Vincent Mailhol <mailhol@kernel.org> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Link: https://patch.msgid.link/20260109144135.8495-3-socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2026-01-15Revert "can: raw: instantly reject unsupported CAN frames"Oliver Hartkopp
This reverts commit 1a620a723853a0f49703c317d52dc6b9602cbaa8 and its follow-up fixes for the introduced dependency issues. commit 1a620a723853 ("can: raw: instantly reject unsupported CAN frames") commit cb2dc6d2869a ("can: Kconfig: select CAN driver infrastructure by default") commit 6abd4577bccc ("can: fix build dependency") commit 5a5aff6338c0 ("can: fix build dependency") The entire problem was caused by the requirement that a new network layer feature needed to know about the protocol capabilities of the CAN devices. Instead of accessing CAN device internal data structures which caused the dependency problems a better approach has been developed which makes use of CAN specific ml_priv data which is accessible from both sides. Cc: Marc Kleine-Budde <mkl@pengutronix.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Vincent Mailhol <mailhol@kernel.org> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Link: https://patch.msgid.link/20260109144135.8495-2-socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2026-01-15samples: configfs: Constify struct configfs_item_operations and ↵Christophe JAILLET
configfs_group_operations 'struct configfs_item_operations' and 'configfs_group_operations' are not modified in this driver. Constifying these structures moves some data to a read-only section, so increases overall security, especially when the structure holds some function pointers. On a x86_64, with allmodconfig: Before: ====== text data bss dec hex filename 7507 6504 64 14075 36fb samples/configfs/configfs_sample.o After: ===== text data bss dec hex filename 7827 6184 64 14075 36fb samples/configfs/configfs_sample.o Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Link: https://lore.kernel.org/r/70c5fd68fcc4d3ba1f18002012fae19acf4ce50b.1767007414.git.christophe.jaillet@wanadoo.fr Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
2026-01-15rust: configfs: replace `kernel::c_str!` with C-StringsTamir Duberstein
C-String literals were added in Rust 1.77. Replace instances of `kernel::c_str!` with C-String literals where possible. Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <lossin@kernel.org> Signed-off-by: Tamir Duberstein <tamird@gmail.com> Acked-by: Andreas Hindborg <a.hindborg@kernel.org> Link: https://lore.kernel.org/r/20251222-cstr-configfs-v1-1-cc1665c51c43@gmail.com Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
2026-01-15arm64: dts: amlogic: Enable the npu node on Radxa Zero 2Ricardo Pardini
The Zero2 is also an A311D just like the VIM3, enable its npu. Signed-off-by: Ricardo Pardini <ricardo@pardini.net> Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org> Link: https://patch.msgid.link/20260114-arm64-dts-amlogic-radxa-zero2-additions-v1-1-8b5cdf328fde@pardini.net Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
2026-01-15arm64: dts: amlogic: g12: assign the MMC A signal clockJerome Brunet
The amlogic MMC driver operate with the assumption that MMC clock is configured to provide 24MHz. It uses this path for low rates such as 400kHz. Assign the clock to make sure it is properly configured Fixes: 8a6b3ca2d361 ("arm64: dts: meson: g12a: add SDIO controller") Signed-off-by: Jerome Brunet <jbrunet@baylibre.com> Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org> Link: https://patch.msgid.link/20260114-amlogic-mmc-clocks-followup-v1-6-a999fafbe0aa@baylibre.com Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
2026-01-15arm64: dts: amlogic: g12: assign the MMC B and C signal clocksJerome Brunet
The amlogic MMC driver operate with the assumption that MMC clock is configured to provide 24MHz. It uses this path for low rates such as 400kHz. Assign the clocks to make sure they are properly configured Fixes: 4759fd87b928 ("arm64: dts: meson: g12a: add mmc nodes") Signed-off-by: Jerome Brunet <jbrunet@baylibre.com> Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org> Link: https://patch.msgid.link/20260114-amlogic-mmc-clocks-followup-v1-5-a999fafbe0aa@baylibre.com Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
2026-01-15arm64: dts: amlogic: gx: assign the MMC signal clocksJerome Brunet
The amlogic MMC driver operate with the assumption that MMC clock is configured to provide 24MHz. It uses this path for low rates such as 400kHz. Assign the clocks to make sure they are properly configured Fixes: 50662499f911 ("ARM64: dts: meson-gx: Use correct mmc clock source 0") Signed-off-by: Jerome Brunet <jbrunet@baylibre.com> Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org> Link: https://patch.msgid.link/20260114-amlogic-mmc-clocks-followup-v1-4-a999fafbe0aa@baylibre.com Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
2026-01-15arm64: dts: amlogic: axg: assign the MMC signal clocksJerome Brunet
The amlogic MMC driver operate with the assumption that MMC clock is configured to provide 24MHz. It uses this path for low rates such as 400kHz. Assign the clocks to make sure they are properly configured Fixes: 221cf34bac54 ("ARM64: dts: meson-axg: enable the eMMC controller") Signed-off-by: Jerome Brunet <jbrunet@baylibre.com> Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org> Link: https://patch.msgid.link/20260114-amlogic-mmc-clocks-followup-v1-3-a999fafbe0aa@baylibre.com Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
2026-01-15arm64: dts: amlogic: a1: align the mmc clock setupJerome Brunet
The amlogic MMC driver operate with the assumption that MMC clock is configured to provide 24MHz. It uses this path for low rates such as 400kHz. A1 is particular in the way that is already has the mmc clock set to 24MHz by forcing the mux to select the board crystal. It works too, it is just slightly less readable. Align with what is being done with the other Amlogic platforms. Signed-off-by: Jerome Brunet <jbrunet@baylibre.com> Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org> Link: https://patch.msgid.link/20260114-amlogic-mmc-clocks-followup-v1-2-a999fafbe0aa@baylibre.com Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
2026-01-15arm64: dts: amlogic: c3: assign the MMC signal clocksJerome Brunet
The amlogic MMC driver operate with the assumption that MMC clock is configured to provide 24MHz. It uses this path for low rates such as 400kHz. Assign the clocks to make sure they are properly configured Fixes: 520b792e8317 ("arm64: dts: amlogic: add some device nodes for C3") Signed-off-by: Jerome Brunet <jbrunet@baylibre.com> Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org> Link: https://patch.msgid.link/20260114-amlogic-mmc-clocks-followup-v1-1-a999fafbe0aa@baylibre.com Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
2026-01-15mshv: handle gpa intercepts for arm64Anirudh Rayabharam (Microsoft)
The mshv driver now uses movable pages for guests. For arm64 guests to be functional, handle gpa intercepts for arm64 too (the current code implements handling only for x86). Move some arch-agnostic functions out of #ifdefs so that they can be re-used. Fixes: b9a66cd5ccbb ("mshv: Add support for movable memory regions") Signed-off-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com> Signed-off-by: Wei Liu <wei.liu@kernel.org>
2026-01-15mshv: add definitions for arm64 gpa interceptsAnirudh Rayabharam (Microsoft)
Add definitions required for handling GPA intercepts on arm64. Signed-off-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com> Reviewed-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com> Signed-off-by: Wei Liu <wei.liu@kernel.org>
2026-01-15mshv: Add __user attribute to argument passed to access_ok()Michael Kelley
access_ok() expects its first argument to have the __user attribute since it is checking access to user space. Current code passes an argument that lacks that attribute, resulting in 'sparse' flagging the incorrect usage. However, the compiler doesn't generate code based on the attribute, so there's no actual bug. In the interest of general correctness and to avoid noise from sparse, add the __user attribute. No functional change. Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202512141339.791TCKnB-lkp@intel.com/ Signed-off-by: Michael Kelley <mhklinux@outlook.com> Reviewed-by: Nuno Das Neves <nunodasneves@linux.microsoft.com> Signed-off-by: Wei Liu <wei.liu@kernel.org>
2026-01-15mshv: Store the result of vfs_poll in a variable of type __poll_tMichael Kelley
vfs_poll() returns a result of type __poll_t, but current code is using an "unsigned int" local variable. The difference is that __poll_t carries the "bitwise" attribute. This attribute is not interpreted by the C compiler; it is only used by 'sparse' to flag incorrect usage of the return value. The return value is used correctly here, so there's no bug, but sparse complains about the type mismatch. In the interest of general correctness and to avoid noise from sparse, change the local variable to type __poll_t. No functional change. Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202512141339.791TCKnB-lkp@intel.com/ Signed-off-by: Michael Kelley <mhklinux@outlook.com> Reviewed-by: Nuno Das Neves <nunodasneves@linux.microsoft.com> Signed-off-by: Wei Liu <wei.liu@kernel.org>
2026-01-15mshv: Align huge page stride with guest mappingStanislav Kinsburskii
Ensure that a stride larger than 1 (huge page) is only used when page points to a head of a huge page and both the guest frame number (gfn) and the operation size (page_count) are aligned to the huge page size (PTRS_PER_PMD). This matches the hypervisor requirement that map/unmap operations for huge pages must be guest-aligned and cover a full huge page. Add mshv_chunk_stride() to encapsulate this alignment and page-order validation, and plumb a huge_page flag into the region chunk handlers. This prevents issuing large-page map/unmap/share operations that the hypervisor would reject due to misaligned guest mappings. Fixes: abceb4297bf8 ("mshv: Fix huge page handling in memory region traversal") Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com> Reviewed-by: Nuno Das Neves <nunodasneves@linux.microsoft.com> Reviewed-by: Michael Kelley <mhklinux@outlook.com> Signed-off-by: Wei Liu <wei.liu@kernel.org>
2026-01-15Drivers: hv: Always do Hyper-V panic notification in hv_kmsg_dump()Michael Kelley
hv_kmsg_dump() currently skips the panic notification entirely if it doesn't get any message bytes to pass to Hyper-V due to an error from kmsg_dump_get_buffer(). Skipping the notification is undesirable because it leaves the Hyper-V host uncertain about the state of a panic'ed guest. Fix this by always doing the panic notification, even if bytes_written is zero. Also ensure that bytes_written is initialized, which fixes a kernel test robot warning. The warning is actually bogus because kmsg_dump_get_buffer() happens to set bytes_written even if it fails, and in the kernel test robot's CONFIG_PRINTK not set case, hv_kmsg_dump() is never called. But do the initialization for robustness and to quiet the static checker. Fixes: 9c318a1d9b50 ("Drivers: hv: move panic report code from vmbus to hv early init code") Reported-by: kernel test robot <lkp@intel.com> Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Closes: https://lore.kernel.org/all/202512172103.OcUspn1Z-lkp@intel.com/ Signed-off-by: Michael Kelley <mhklinux@outlook.com> Reviewed-by: Roman Kisel <vdso@mailbox.org> Signed-off-by: Wei Liu <wei.liu@kernel.org>
2026-01-15Drivers: hv: vmbus: fix typo in function name referenceJulia Lawall
Replace cmxchg by cmpxchg. Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr> Reviewed-by: Roman Kisel <vdso@mailbox.org> Signed-off-by: Wei Liu <wei.liu@kernel.org>
2026-01-14drivers/dax: add some missing kerneldoc comment fields for struct dev_daxJohn Groves
Add the missing @align and @memmap_on_memory fields to kerneldoc comment header for struct dev_dax. Also, some other fields were followed by '-' and others by ':'. Fix all to be ':' for actual kerneldoc compliance. Link: https://lkml.kernel.org/r/20260110191804.5739-1-john@groves.net Fixes: 33cf94d71766 ("device-dax: make align a per-device property") Fixes: 4eca0ef49af9 ("dax/kmem: allow kmem to add memory with memmap_on_memory") Signed-off-by: John Groves <john@groves.net> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Joao Martins <joao.m.martins@oracle.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14mm: numa,memblock: include <asm/numa.h> for 'numa_nodes_parsed'Ben Dooks
The 'numa_nodes_parsed' is defined in <asm/numa.h> but this file is not included in mm/numa_memblks.c (build x86_64) so add this to the incldues to fix the following sparse warning: mm/numa_memblks.c:13:12: warning: symbol 'numa_nodes_parsed' was not declared. Should it be static? Link: https://lkml.kernel.org/r/20260108101539.229192-1-ben.dooks@codethink.co.uk Fixes: 87482708210f ("mm: introduce numa_memblks") Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: Ben Dooks <ben.dooks@codethink.co.uk> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14mailmap: add entry for Daniel ThompsonDaniel Thompson
My linaro address stopped working a long time ago but I didn't update my mailmap entry. Fix that. Link: https://lkml.kernel.org/r/20260108-mailmap-daniel_thompson_linaro-org-v1-1-83f610876377@kernel.org Signed-off-by: Daniel Thompson <danielt@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14tools/testing/selftests: fix gup_longterm for unknown fsLorenzo Stoakes
Commit 66bce7afbaca ("selftests/mm: fix test result reporting in gup_longterm") introduced a small bug causing unknown filesystems to always result in a test failure. This is because do_test() was updated to use a common reporting path, but this case appears to have been missed. This is problematic for e.g. virtme-ng which uses an overlayfs file system, causing gup_longterm to appear to fail each time due to a test count mismatch: # Planned tests != run tests (50 != 46) # Totals: pass:24 fail:0 xfail:0 xpass:0 skip:22 error:0 The fix is to simply change the return into a break. Link: https://lkml.kernel.org/r/20260106154547.214907-1-lorenzo.stoakes@oracle.com Fixes: 66bce7afbaca ("selftests/mm: fix test result reporting in gup_longterm") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: David Hildenbrand (Red Hat) <david@kernel.org> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com> Cc: Mark Brown <broonie@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Peter Xu <peterx@redhat.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14mm/page_alloc: prevent pcp corruption with SMP=nVlastimil Babka
The kernel test robot has reported: BUG: spinlock trylock failure on UP on CPU#0, kcompactd0/28 lock: 0xffff888807e35ef0, .magic: dead4ead, .owner: kcompactd0/28, .owner_cpu: 0 CPU: 0 UID: 0 PID: 28 Comm: kcompactd0 Not tainted 6.18.0-rc5-00127-ga06157804399 #1 PREEMPT 8cc09ef94dcec767faa911515ce9e609c45db470 Call Trace: <IRQ> __dump_stack (lib/dump_stack.c:95) dump_stack_lvl (lib/dump_stack.c:123) dump_stack (lib/dump_stack.c:130) spin_dump (kernel/locking/spinlock_debug.c:71) do_raw_spin_trylock (kernel/locking/spinlock_debug.c:?) _raw_spin_trylock (include/linux/spinlock_api_smp.h:89 kernel/locking/spinlock.c:138) __free_frozen_pages (mm/page_alloc.c:2973) ___free_pages (mm/page_alloc.c:5295) __free_pages (mm/page_alloc.c:5334) tlb_remove_table_rcu (include/linux/mm.h:? include/linux/mm.h:3122 include/asm-generic/tlb.h:220 mm/mmu_gather.c:227 mm/mmu_gather.c:290) ? __cfi_tlb_remove_table_rcu (mm/mmu_gather.c:289) ? rcu_core (kernel/rcu/tree.c:?) rcu_core (include/linux/rcupdate.h:341 kernel/rcu/tree.c:2607 kernel/rcu/tree.c:2861) rcu_core_si (kernel/rcu/tree.c:2879) handle_softirqs (arch/x86/include/asm/jump_label.h:36 include/trace/events/irq.h:142 kernel/softirq.c:623) __irq_exit_rcu (arch/x86/include/asm/jump_label.h:36 kernel/softirq.c:725) irq_exit_rcu (kernel/softirq.c:741) sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1052) </IRQ> <TASK> RIP: 0010:_raw_spin_unlock_irqrestore (arch/x86/include/asm/preempt.h:95 include/linux/spinlock_api_smp.h:152 kernel/locking/spinlock.c:194) free_pcppages_bulk (mm/page_alloc.c:1494) drain_pages_zone (include/linux/spinlock.h:391 mm/page_alloc.c:2632) __drain_all_pages (mm/page_alloc.c:2731) drain_all_pages (mm/page_alloc.c:2747) kcompactd (mm/compaction.c:3115) kthread (kernel/kthread.c:465) ? __cfi_kcompactd (mm/compaction.c:3166) ? __cfi_kthread (kernel/kthread.c:412) ret_from_fork (arch/x86/kernel/process.c:164) ? __cfi_kthread (kernel/kthread.c:412) ret_from_fork_asm (arch/x86/entry/entry_64.S:255) </TASK> Matthew has analyzed the report and identified that in drain_page_zone() we are in a section protected by spin_lock(&pcp->lock) and then get an interrupt that attempts spin_trylock() on the same lock. The code is designed to work this way without disabling IRQs and occasionally fail the trylock with a fallback. However, the SMP=n spinlock implementation assumes spin_trylock() will always succeed, and thus it's normally a no-op. Here the enabled lock debugging catches the problem, but otherwise it could cause a corruption of the pcp structure. The problem has been introduced by commit 574907741599 ("mm/page_alloc: leave IRQs enabled for per-cpu page allocations"). The pcp locking scheme recognizes the need for disabling IRQs to prevent nesting spin_trylock() sections on SMP=n, but the need to prevent the nesting in spin_lock() has not been recognized. Fix it by introducing local wrappers that change the spin_lock() to spin_lock_iqsave() with SMP=n and use them in all places that do spin_lock(&pcp->lock). [vbabka@suse.cz: add pcp_ prefix to the spin_lock_irqsave wrappers, per Steven] Link: https://lkml.kernel.org/r/20260105-fix-pcp-up-v1-1-5579662d2071@suse.cz Fixes: 574907741599 ("mm/page_alloc: leave IRQs enabled for per-cpu page allocations") Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reported-by: kernel test robot <oliver.sang@intel.com> Closes: https://lore.kernel.org/oe-lkp/202512101320.e2f2dd6f-lkp@intel.com Analyzed-by: Matthew Wilcox <willy@infradead.org> Link: https://lore.kernel.org/all/aUW05pyc9nZkvY-1@casper.infradead.org/ Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Brendan Jackman <jackmanb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Zi Yan <ziy@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14iommu/sva: include mmu_notifier.h headerCarlos Llamas
A call to mmu_notifier_arch_invalidate_secondary_tlbs() was introduced in commit e37d5a2d60a3 ("iommu/sva: invalidate stale IOTLB entries for kernel address space") but without explicitly adding its corresponding header file <linux/mmu_notifier.h>. This was evidenced while trying to enable compile testing support for IOMMU_SVA: config IOMMU_SVA select IOMMU_MM_DATA - bool + bool "Shared Virtual Addressing" if COMPILE_TEST The thing is for certain architectures this header file is indirectly included via <asm/tlbflush.h>. However, for others such as 32-bit arm the header is missing and it results in a build failure: $ make ARCH=arm allmodconfig [...] drivers/iommu/iommu-sva.c:340:3: error: call to undeclared function 'mmu_notifier_arch_invalidate_secondary_tlbs' [...] 340 | mmu_notifier_arch_invalidate_secondary_tlbs(iommu_mm->mm, start, end); | ^ Fix this by including the appropriate header file. Link: https://lkml.kernel.org/r/20260105190747.625082-1-cmllamas@google.com Fixes: e37d5a2d60a3 ("iommu/sva: invalidate stale IOTLB entries for kernel address space") Signed-off-by: Carlos Llamas <cmllamas@google.com> Cc: Baolu Lu <baolu.lu@linux.intel.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Joerg Roedel <joro@8bytes.org> Cc: Kevin Tian <kevin.tian@intel.com> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Vasant Hegde <vasant.hegde@amd.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14mm: kmsan: fix poisoning of high-order non-compound pagesRyan Roberts
kmsan_free_page() is called by the page allocator's free_pages_prepare() during page freeing. Its job is to poison all the memory covered by the page. It can be called with an order-0 page, a compound high-order page or a non-compound high-order page. But page_size() only works for order-0 and compound pages. For a non-compound high-order page it will incorrectly return PAGE_SIZE. The implication is that the tail pages of a high-order non-compound page do not get poisoned at free, so any invalid access while they are free could go unnoticed. It looks like the pages will be poisoned again at allocation time, so that would bookend the window. Fix this by using the order parameter to calculate the size. Link: https://lkml.kernel.org/r/20260104134348.3544298-1-ryan.roberts@arm.com Fixes: b073d7f8aee4 ("mm: kmsan: maintain KMSAN metadata for page operations") Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Reviewed-by: Alexander Potapenko <glider@google.com> Tested-by: Alexander Potapenko <glider@google.com> Cc: Dmitriy Vyukov <dvyukov@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Marco Elver <elver@google.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14tools/testing/selftests: add forked (un)/faulted VMA merge testsLorenzo Stoakes
Now we correctly handle forked faulted/unfaulted merge on mremap(), exhaustively assert that we handle this correctly. Do this in the less duplicative way by adding a new merge_with_fork fixture and forked/unforked variants, and abstract the forking logic as necessary to avoid code duplication with this also. Link: https://lkml.kernel.org/r/1daf76d89fdb9d96f38a6a0152d8f3c2e9e30ac7.1767638272.git.lorenzo.stoakes@oracle.com Fixes: 879bca0a2c4f ("mm/vma: fix incorrectly disallowed anonymous VMA merges") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: David Hildenbrand (Red Hat) <david@kernel.org> Cc: Jann Horn <jannh@google.com> Cc: Jeongjun Park <aha310510@gmail.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yeoreum Yun <yeoreum.yun@arm.com> Cc: Harry Yoo <harry.yoo@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14mm/vma: enforce VMA fork limit on unfaulted,faulted mremap merge tooLorenzo Stoakes
The is_mergeable_anon_vma() function uses vmg->middle as the source VMA. However when merging a new VMA, this field is NULL. In all cases except mremap(), the new VMA will either be newly established and thus lack an anon_vma, or will be an expansion of an existing VMA thus we do not care about whether VMA is CoW'd or not. In the case of an mremap(), we can end up in a situation where we can accidentally allow an unfaulted/faulted merge with a VMA that has been forked, violating the general rule that we do not permit this for reasons of anon_vma lock scalability. Now we have the ability to be aware of the fact we are copying a VMA and also know which VMA that is, we can explicitly check for this, so do so. This is pertinent since commit 879bca0a2c4f ("mm/vma: fix incorrectly disallowed anonymous VMA merges"), as this patch permits unfaulted/faulted merges that were previously disallowed running afoul of this issue. While we are here, vma_had_uncowed_parents() is a confusing name, so make it simple and rename it to vma_is_fork_child(). Link: https://lkml.kernel.org/r/6e2b9b3024ae1220961c8b81d74296d4720eaf2b.1767638272.git.lorenzo.stoakes@oracle.com Fixes: 879bca0a2c4f ("mm/vma: fix incorrectly disallowed anonymous VMA merges") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Harry Yoo <harry.yoo@oracle.com> Reviewed-by: Jeongjun Park <aha310510@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand (Red Hat) <david@kernel.org> Cc: Jann Horn <jannh@google.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Rik van Riel <riel@surriel.com> Cc: Yeoreum Yun <yeoreum.yun@arm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14tools/testing/selftests: add tests for !tgt, src mremap() mergesLorenzo Stoakes
Test that mremap()'ing a VMA into a position such that the target VMA on merge is unfaulted and the source faulted is correctly performed. We cover 4 cases: 1. Previous VMA unfaulted: copied -----| v |-----------|.............| | unfaulted |(faulted VMA)| |-----------|.............| prev target = prev, expand prev to cover. 2. Next VMA unfaulted: copied -----| v |.............|-----------| |(faulted VMA)| unfaulted | |.............|-----------| next target = next, expand next to cover. 3. Both adjacent VMAs unfaulted: copied -----| v |-----------|.............|-----------| | unfaulted |(faulted VMA)| unfaulted | |-----------|.............|-----------| prev next target = prev, expand prev to cover. 4. prev unfaulted, next faulted: copied -----| v |-----------|.............|-----------| | unfaulted |(faulted VMA)| faulted | |-----------|.............|-----------| prev next target = prev, expand prev to cover. Essentially equivalent to 3, but with additional requirement that next's anon_vma is the same as the copied VMA's. Each of these are performed with MREMAP_DONTUNMAP set, which will cause a KASAN assert for UAF or an assert on zero refcount anon_vma if a bug exists with correctly propagating anon_vma state in each scenario. Link: https://lkml.kernel.org/r/f903af2930c7c2c6e0948c886b58d0f42d8e8ba3.1767638272.git.lorenzo.stoakes@oracle.com Fixes: 879bca0a2c4f ("mm/vma: fix incorrectly disallowed anonymous VMA merges") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: David Hildenbrand (Red Hat) <david@kernel.org> Cc: Jann Horn <jannh@google.com> Cc: Jeongjun Park <aha310510@gmail.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yeoreum Yun <yeoreum.yun@arm.com> Cc: Harry Yoo <harry.yoo@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14mm/vma: fix anon_vma UAF on mremap() faulted, unfaulted mergeLorenzo Stoakes
Patch series "mm/vma: fix anon_vma UAF on mremap() faulted, unfaulted merge", v2. Commit 879bca0a2c4f ("mm/vma: fix incorrectly disallowed anonymous VMA merges") introduced the ability to merge previously unavailable VMA merge scenarios. However, it is handling merges incorrectly when it comes to mremap() of a faulted VMA adjacent to an unfaulted VMA. The issues arise in three cases: 1. Previous VMA unfaulted: copied -----| v |-----------|.............| | unfaulted |(faulted VMA)| |-----------|.............| prev 2. Next VMA unfaulted: copied -----| v |.............|-----------| |(faulted VMA)| unfaulted | |.............|-----------| next 3. Both adjacent VMAs unfaulted: copied -----| v |-----------|.............|-----------| | unfaulted |(faulted VMA)| unfaulted | |-----------|.............|-----------| prev next This series fixes each of these cases, and introduces self tests to assert that the issues are corrected. I also test a further case which was already handled, to assert that my changes continues to correctly handle it: 4. prev unfaulted, next faulted: copied -----| v |-----------|.............|-----------| | unfaulted |(faulted VMA)| faulted | |-----------|.............|-----------| prev next This bug was discovered via a syzbot report, linked to in the first patch in the series, I confirmed that this series fixes the bug. I also discovered that we are failing to check that the faulted VMA was not forked when merging a copied VMA in cases 1-3 above, an issue this series also addresses. I also added self tests to assert that this is resolved (and confirmed that the tests failed prior to this). I also cleaned up vma_expand() as part of this work, renamed vma_had_uncowed_parents() to vma_is_fork_child() as the previous name was unduly confusing, and simplified the comments around this function. This patch (of 4): Commit 879bca0a2c4f ("mm/vma: fix incorrectly disallowed anonymous VMA merges") introduced the ability to merge previously unavailable VMA merge scenarios. The key piece of logic introduced was the ability to merge a faulted VMA immediately next to an unfaulted VMA, which relies upon dup_anon_vma() to correctly handle anon_vma state. In the case of the merge of an existing VMA (that is changing properties of a VMA and then merging if those properties are shared by adjacent VMAs), dup_anon_vma() is invoked correctly. However in the case of the merge of a new VMA, a corner case peculiar to mremap() was missed. The issue is that vma_expand() only performs dup_anon_vma() if the target (the VMA that will ultimately become the merged VMA): is not the next VMA, i.e. the one that appears after the range in which the new VMA is to be established. A key insight here is that in all other cases other than mremap(), a new VMA merge either expands an existing VMA, meaning that the target VMA will be that VMA, or would have anon_vma be NULL. Specifically: * __mmap_region() - no anon_vma in place, initial mapping. * do_brk_flags() - expanding an existing VMA. * vma_merge_extend() - expanding an existing VMA. * relocate_vma_down() - no anon_vma in place, initial mapping. In addition, we are in the unique situation of needing to duplicate anon_vma state from a VMA that is neither the previous or next VMA being merged with. dup_anon_vma() deals exclusively with the target=unfaulted, src=faulted case. This leaves four possibilities, in each case where the copied VMA is faulted: 1. Previous VMA unfaulted: copied -----| v |-----------|.............| | unfaulted |(faulted VMA)| |-----------|.............| prev target = prev, expand prev to cover. 2. Next VMA unfaulted: copied -----| v |.............|-----------| |(faulted VMA)| unfaulted | |.............|-----------| next target = next, expand next to cover. 3. Both adjacent VMAs unfaulted: copied -----| v |-----------|.............|-----------| | unfaulted |(faulted VMA)| unfaulted | |-----------|.............|-----------| prev next target = prev, expand prev to cover. 4. prev unfaulted, next faulted: copied -----| v |-----------|.............|-----------| | unfaulted |(faulted VMA)| faulted | |-----------|.............|-----------| prev next target = prev, expand prev to cover. Essentially equivalent to 3, but with additional requirement that next's anon_vma is the same as the copied VMA's. This is covered by the existing logic. To account for this very explicitly, we introduce vma_merge_copied_range(), which sets a newly introduced vmg->copied_from field, then invokes vma_merge_new_range() which handles the rest of the logic. We then update the key vma_expand() function to clean up the logic and make what's going on clearer, making the 'remove next' case less special, before invoking dup_anon_vma() unconditionally should we be copying from a VMA. Note that in case 3, the if (remove_next) ... branch will be a no-op, as next=src in this instance and src is unfaulted. In case 4, it won't be, but since in this instance next=src and it is faulted, this will have required tgt=faulted, src=faulted to be compatible, meaning that next->anon_vma == vmg->copied_from->anon_vma, and thus a single dup_anon_vma() of next suffices to copy anon_vma state for the copied-from VMA also. If we are copying from a VMA in a successful merge we must _always_ propagate anon_vma state. This issue can be observed most directly by invoked mremap() to move around a VMA and cause this kind of merge with the MREMAP_DONTUNMAP flag specified. This will result in unlink_anon_vmas() being called after failing to duplicate anon_vma state to the target VMA, which results in the anon_vma itself being freed with folios still possessing dangling pointers to the anon_vma and thus a use-after-free bug. This bug was discovered via a syzbot report, which this patch resolves. We further make a change to update the mergeable anon_vma check to assert the copied-from anon_vma did not have CoW parents, as otherwise dup_anon_vma() might incorrectly propagate CoW ancestors from the next VMA in case 4 despite the anon_vma's being identical for both VMAs. Link: https://lkml.kernel.org/r/cover.1767638272.git.lorenzo.stoakes@oracle.com Link: https://lkml.kernel.org/r/b7930ad2b1503a657e29fe928eb33061d7eadf5b.1767638272.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Fixes: 879bca0a2c4f ("mm/vma: fix incorrectly disallowed anonymous VMA merges") Reported-by: syzbot+b165fc2e11771c66d8ba@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/694a2745.050a0220.19928e.0017.GAE@google.com/ Reported-by: syzbot+5272541ccbbb14e2ec30@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/694e3dc6.050a0220.35954c.0066.GAE@google.com/ Reviewed-by: Harry Yoo <harry.yoo@oracle.com> Reviewed-by: Jeongjun Park <aha310510@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand (Red Hat) <david@kernel.org> Cc: Jann Horn <jannh@google.com> Cc: Yeoreum Yun <yeoreum.yun@arm.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Rik van Riel <riel@surriel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14mm/zswap: fix error pointer free in zswap_cpu_comp_prepare()Pavel Butsykin
crypto_alloc_acomp_node() may return ERR_PTR(), but the fail path checks only for NULL and can pass an error pointer to crypto_free_acomp(). Use IS_ERR_OR_NULL() to only free valid acomp instances. Link: https://lkml.kernel.org/r/20251231074638.2564302-1-pbutsykin@cloudlinux.com Fixes: 779b9955f643 ("mm: zswap: move allocations during CPU init outside the lock") Signed-off-by: Pavel Butsykin <pbutsykin@cloudlinux.com> Reviewed-by: SeongJae Park <sj@kernel.org> Acked-by: Yosry Ahmed <yosry.ahmed@linux.dev> Acked-by: Nhat Pham <nphamcs@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14mm/damon/sysfs-scheme: cleanup access_pattern subdirs on scheme dir setup ↵SeongJae Park
failure When a DAMOS-scheme DAMON sysfs directory setup fails after setup of access_pattern/ directory, subdirectories of access_pattern/ directory are not cleaned up. As a result, DAMON sysfs interface is nearly broken until the system reboots, and the memory for the unremoved directory is leaked. Cleanup the directories under such failures. Link: https://lkml.kernel.org/r/20251225023043.18579-5-sj@kernel.org Fixes: 9bbb820a5bd5 ("mm/damon/sysfs: support DAMOS quotas") Signed-off-by: SeongJae Park <sj@kernel.org> Cc: chongjiapeng <jiapeng.chong@linux.alibaba.com> Cc: <stable@vger.kernel.org> # 5.18.x Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14mm/damon/sysfs-scheme: cleanup quotas subdirs on scheme dir setup failureSeongJae Park
When a DAMOS-scheme DAMON sysfs directory setup fails after setup of quotas/ directory, subdirectories of quotas/ directory are not cleaned up. As a result, DAMON sysfs interface is nearly broken until the system reboots, and the memory for the unremoved directory is leaked. Cleanup the directories under such failures. Link: https://lkml.kernel.org/r/20251225023043.18579-4-sj@kernel.org Fixes: 1b32234ab087 ("mm/damon/sysfs: support DAMOS watermarks") Signed-off-by: SeongJae Park <sj@kernel.org> Cc: chongjiapeng <jiapeng.chong@linux.alibaba.com> Cc: <stable@vger.kernel.org> # 5.18.x Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14mm/damon/sysfs: cleanup attrs subdirs on context dir setup failureSeongJae Park
When a context DAMON sysfs directory setup is failed after setup of attrs/ directory, subdirectories of attrs/ directory are not cleaned up. As a result, DAMON sysfs interface is nearly broken until the system reboots, and the memory for the unremoved directory is leaked. Cleanup the directories under such failures. Link: https://lkml.kernel.org/r/20251225023043.18579-3-sj@kernel.org Fixes: c951cd3b8901 ("mm/damon: implement a minimal stub for sysfs-based DAMON interface") Signed-off-by: SeongJae Park <sj@kernel.org> Cc: chongjiapeng <jiapeng.chong@linux.alibaba.com> Cc: <stable@vger.kernel.org> # 5.18.x Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14mm/damon/sysfs: cleanup intervals subdirs on attrs dir setup failureSeongJae Park
Patch series "mm/damon/sysfs: free setup failures generated zombie sub-sub dirs". Some DAMON sysfs directory setup functions generates its sub and sub-sub directories. For example, 'monitoring_attrs/' directory setup creates 'intervals/' and 'intervals/intervals_goal/' directories under 'monitoring_attrs/' directory. When such sub-sub directories are successfully made but followup setup is failed, the setup function should recursively clean up the subdirectories. However, such setup functions are only dereferencing sub directory reference counters. As a result, under certain setup failures, the sub-sub directories keep having non-zero reference counters. It means the directories cannot be removed like zombies, and the memory for the directories cannot be freed. The user impact of this issue is limited due to the following reasons. When the issue happens, the zombie directories are still taking the path. Hence attempts to generate the directories again will fail, without additional memory leak. This means the upper bound memory leak is limited. Nonetheless this also implies controlling DAMON with a feature that requires the setup-failed sysfs files will be impossible until the system reboots. Also, the setup operations are quite simple. The certain failures would hence only rarely happen, and are difficult to artificially trigger. This patch (of 4): When attrs/ DAMON sysfs directory setup is failed after setup of intervals/ directory, intervals/intervals_goal/ directory is not cleaned up. As a result, DAMON sysfs interface is nearly broken until the system reboots, and the memory for the unremoved directory is leaked. Cleanup the directory under such failures. Link: https://lkml.kernel.org/r/20251225023043.18579-1-sj@kernel.org Link: https://lkml.kernel.org/r/20251225023043.18579-2-sj@kernel.org Fixes: 8fbbcbeaafeb ("mm/damon/sysfs: implement intervals tuning goal directory") Signed-off-by: SeongJae Park <sj@kernel.org> Cc: chongjiapeng <jiapeng.chong@linux.alibaba.com> Cc: <stable@vger.kernel.org> # 6.15.x Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14mm/damon/core: remove call_control in inactive contextsSeongJae Park
If damon_call() is executed against a DAMON context that is not running, the function returns error while keeping the damon_call_control object linked to the context's call_controls list. Let's suppose the object is deallocated after the damon_call(), and yet another damon_call() is executed against the same context. The function tries to add the new damon_call_control object to the call_controls list, which still has the pointer to the previous damon_call_control object, which is deallocated. As a result, use-after-free happens. This can actually be triggered using the DAMON sysfs interface. It is not easily exploitable since it requires the sysfs write permission and making a definitely weird file writes, though. Please refer to the report for more details about the issue reproduction steps. Fix the issue by making two changes. Firstly, move the final kdamond_call() for cancelling all existing damon_call() requests from terminating DAMON context to be done before the ctx->kdamond reset. This makes any code that sees NULL ctx->kdamond can safely assume the context may not access damon_call() requests anymore. Secondly, let damon_call() to cleanup the damon_call_control objects that were added to the already-terminated DAMON context, before returning the error. Link: https://lkml.kernel.org/r/20251231012315.75835-1-sj@kernel.org Fixes: 004ded6bee11 ("mm/damon: accept parallel damon_call() requests") Signed-off-by: SeongJae Park <sj@kernel.org> Reported-by: JaeJoon Jung <rgbi3307@gmail.com> Closes: https://lore.kernel.org/20251224094401.20384-1-rgbi3307@gmail.com Cc: <stable@vger.kernel.org> # 6.17.x Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14powerpc/watchdog: add support for hardlockup_sys_info sysctlFeng Tang
Commit a9af76a78760 ("watchdog: add sys_info sysctls to dump sys info on system lockup") adds 'hardlock_sys_info' systcl knob for general kernel watchdog to control what kinds of system debug info to be dumped on hardlockup. Add similar support in powerpc watchdog code to make the sysctl knob more general, which also fixes a compiling warning in general watchdog code reported by 0day bot. Link: https://lkml.kernel.org/r/20251231080309.39642-1-feng.tang@linux.alibaba.com Fixes: a9af76a78760 ("watchdog: add sys_info sysctls to dump sys info on system lockup") Signed-off-by: Feng Tang <feng.tang@linux.alibaba.com> Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202512030920.NFKtekA7-lkp@intel.com/ Suggested-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14mips: fix HIGHMEM initializationMike Rapoport (Microsoft)
Commit 6faea3422e3b ("arch, mm: streamline HIGHMEM freeing") overzealously removed mem_init_free_highmem() function that beside freeing high memory pages checked for CPU support for high memory as a prerequisite. Partially restore mem_init_free_highmem() with a new highmem_init() name and make it discard high memory in case there is no CPU support for it. Link: https://lkml.kernel.org/r/20251231105701.519711-1-rppt@kernel.org Fixes: 6faea3422e3b ("arch, mm: streamline HIGHMEM freeing") Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reported-by: Markus Stockhausen <markus.stockhausen@gmx.de> Cc: Chris Packham <chris.packham@alliedtelesis.co.nz> Cc: Hauke Mehrtens <hauke@hauke-m.de> Cc: Jonas Jelonek <jelonek.jonas@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleinxer <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14mm/hugetlb: ignore hugepage kernel args if hugepages are unsupportedSourabh Jain
Skip processing hugepage kernel arguments (hugepagesz, hugepages, and default_hugepagesz) when hugepages are not supported by the architecture. Some architectures may need to disable hugepages based on conditions discovered during kernel boot. The hugepages_supported() helper allows architecture code to advertise whether hugepages are supported. Currently, normal hugepage allocation is guarded by hugepages_supported(), but gigantic hugepages are allocated regardless of this check. This causes problems on powerpc for fadump (firmware- assisted dump). In the fadump (firmware-assisted dump) scenario, a production kernel crash causes the system to boot into a special kernel whose sole purpose is to collect the memory dump and reboot. Features such as hugepages are not required in this environment and should be disabled. For example, when the fadump kernel boots with the following kernel arguments: default_hugepagesz=1GB hugepagesz=1GB hugepages=200 Before this patch, the kernel prints the following logs: HugeTLB: allocating 200 of page size 1.00 GiB failed. Only allocated 58 hugepages. HugeTLB support is disabled! HugeTLB: huge pages not supported, ignoring associated command-line parameters hugetlbfs: disabling because there are no supported hugepage sizes Even though the logs state that HugeTLB support is disabled, gigantic hugepages are still allocated. This causes the fadump kernel to run out of memory during boot. After this patch is applied, the kernel prints the following logs for the same command line: HugeTLB: hugepages unsupported, ignoring default_hugepagesz=1GB cmdline HugeTLB: hugepages unsupported, ignoring hugepagesz=1GB cmdline HugeTLB: hugepages unsupported, ignoring hugepages=200 cmdline HugeTLB support is disabled! hugetlbfs: disabling because there are no supported hugepage sizes To fix the issue, gigantic hugepage allocation should be guarded by hugepages_supported(). Previously, two approaches were proposed to bring gigantic hugepage allocation under hugepages_supported(): [1] Check hugepages_supported() in the generic code before allocating gigantic hugepages [2] Make arch_hugetlb_valid_size() return false for all hugetlb sizes Approach [2] has two minor issues: 1. It prints misleading logs about invalid hugepage sizes 2. The kernel still processes hugepage kernel arguments unnecessarily To control gigantic hugepage allocation, skip processing hugepage kernel arguments (default_hugepagesz, hugepagesz and hugepages) when hugepages_supported() returns false. Note for backporting: This fix is a partial reversion of the commit mentioned in the Fixes tag and is only valid once the change referenced by the Depends-on tag is present. When backporting this patch, the commit mentioned in the Depends-on tag must be included first. Link: https://lore.kernel.org/all/20250121150419.1342794-1-sourabhjain@linux.ibm.com/ [1] Link: https://lore.kernel.org/all/20250128043358.163372-1-sourabhjain@linux.ibm.com/ [2] Link: https://lkml.kernel.org/r/20251224115524.1272010-1-sourabhjain@linux.ibm.com Fixes: c2833a5bf75b ("hugetlbfs: fix changes to command line processing") Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com> Depends-on: 2354ad252b66 ("powerpc/mm: Update default hugetlb size early") Acked-by: David Hildenbrand (Red Hat) <david@kernel.org> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Muchun Song <muchun.song@linux.dev> Cc: Oscar Salvador <osalvador@suse.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14mm/page_alloc: make percpu_pagelist_high_fraction reads lock-freeAboorva Devarajan
When page isolation loops indefinitely during memory offline, reading /proc/sys/vm/percpu_pagelist_high_fraction blocks on pcp_batch_high_lock, causing hung task warnings. Make procfs reads lock-free since percpu_pagelist_high_fraction is a simple integer with naturally atomic reads, writers still serialize via the mutex. This prevents hung task warnings when reading the procfs file during long-running memory offline operations. [akpm@linux-foundation.org: add comment, per Michal] Link: https://lkml.kernel.org/r/aS_y9AuJQFydLEXo@tiehlicka Link: https://lkml.kernel.org/r/20251201060009.1420792-1-aboorvad@linux.ibm.com Signed-off-by: Aboorva Devarajan <aboorvad@linux.ibm.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Brendan Jackman <jackmanb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zi Yan <ziy@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14mm/damon/core: get memcg reference before accessShakeel Butt
The commit b74a120bcf507 ("mm/damon/core: implement DAMOS_QUOTA_NODE_MEMCG_USED_BP") added accesses to memcg structure without getting reference to it. This is unsafe. Let's get the reference before accessing the memcg. Link: https://lkml.kernel.org/r/20251225002904.139543-1-shakeel.butt@linux.dev Fixes: b74a120bcf507 ("mm/damon/core: implement DAMOS_QUOTA_NODE_MEMCG_USED_BP") Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14kho: validate preserved memory map during populationPasha Tatashin
If the previous kernel enabled KHO but did not call kho_finalize() (e.g., CONFIG_LIVEUPDATE=n or userspace skipped the finalization step), the 'preserved-memory-map' property in the FDT remains empty/zero. Previously, kho_populate() would succeed regardless of the memory map's state, reserving the incoming scratch regions in memblock. However, kho_memory_init() would later fail to deserialize the empty map. By that time, the scratch regions were already registered, leading to partial initialization and subsequent list corruption (freeing scratch area twice) during kho_init(). Move the validation of the preserved memory map earlier into kho_populate(). If the memory map is empty/NULL: 1. Abort kho_populate() immediately with -ENOENT. 2. Do not register or reserve the incoming scratch memory, allowing the new kernel to reclaim those pages as standard free memory. 3. Leave the global 'kho_in' state uninitialized. Consequently, kho_memory_init() sees no active KHO context (kho_in.mem_chunks_phys is 0) and falls back to kho_reserve_scratch(), allocating fresh scratch memory as if it were a standard cold boot. Link: https://lkml.kernel.org/r/20251223140140.2090337-1-pasha.tatashin@soleen.com Fixes: de51999e687c ("kho: allow memory preservation state updates after finalization") Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reported-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Closes: https://lore.kernel.org/all/20251218215613.GA17304@ranerica-svr.sc.intel.com Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Tested-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14lib/buildid: use __kernel_read() for sleepable contextShakeel Butt
Prevent a "BUG: unable to handle kernel NULL pointer dereference in filemap_read_folio". For the sleepable context, convert freader to use __kernel_read() instead of direct page cache access via read_cache_folio(). This simplifies the faultable code path by using the standard kernel file reading interface which handles all the complexity of reading file data. At the moment we are not changing the code for non-sleepable context which uses filemap_get_folio() and only succeeds if the target folios are already in memory and up-to-date. The reason is to keep the patch simple and easier to backport to stable kernels. Syzbot repro does not crash the kernel anymore and the selftests run successfully. In the follow up we will make __kernel_read() with IOCB_NOWAIT work for non-sleepable contexts. In addition, I would like to replace the secretmem check with a more generic approach and will add fstest for the buildid code. Link: https://lkml.kernel.org/r/20251222205859.3968077-1-shakeel.butt@linux.dev Fixes: ad41251c290d ("lib/buildid: implement sleepable build_id_parse() API") Reported-by: syzbot+09b7d050e4806540153d@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=09b7d050e4806540153d Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: Jinchao Wang <wangjinchao600@gmail.com> Link: https://lkml.kernel.org/r/aUteBPWPYzVWIZFH@ndev Reviewed-by: Christian Brauner <brauner@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Daniel Borkman <daniel@iogearbox.net> Cc: "Darrick J. Wong" <djwong@kernel.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14docs: kernel-parameters: add kfence parametersMarco Elver
Add a brief summary for KFENCE's kernel command-line parameters in admin-guide/kernel-parameters. Link: https://lkml.kernel.org/r/20251222150018.1349672-1-elver@google.com Signed-off-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitriy Vyukov <dvyukov@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>