kernel.git/kernel, branch linux-6.1.y

tracing: Fix to set write permission to per-cpu buffer_size_kb

2026-03-04T12:20:54Z

[ Upstream commit f844282deed7481cf2f813933229261e27306551 ] Since the per-cpu buffer_size_kb file is writable for changing per-cpu ring buffer size, the file should have the write access permission. Cc: stable@vger.kernel.org Cc: Mathieu Desnoyers Link: https://patch.msgid.link/177071301597.2293046.11683339475076917920.stgit@mhiramat.tok.corp.google.com Fixes: 21ccc9cd7211 ("tracing: Disable "other" permission bits in the tracefs files") Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google) Signed-off-by: Sasha Levin

kexec: derive purgatory entry from symbol

2026-03-04T12:20:50Z

[ Upstream commit 480e1d5c64bb14441f79f2eb9421d5e26f91ea3d ] kexec_load_purgatory() derives image->start by locating e_entry inside an SHF_EXECINSTR section. If the purgatory object contains multiple executable sections with overlapping sh_addr, the entrypoint check can match more than once and trigger a WARN. Derive the entry section from the purgatory_start symbol when present and compute image->start from its final placement. Keep the existing e_entry fallback for purgatories that do not expose the symbol. WARNING: kernel/kexec_file.c:1009 at kexec_load_purgatory+0x395/0x3c0, CPU#10: kexec/1784 Call Trace: bzImage64_load+0x133/0xa00 __do_sys_kexec_file_load+0x2b3/0x5c0 do_syscall_64+0x81/0x610 entry_SYSCALL_64_after_hwframe+0x76/0x7e [me@linux.beauty: move helper to avoid forward declaration, per Baoquan] Link: https://lkml.kernel.org/r/20260128043511.316860-1-me@linux.beauty Link: https://lkml.kernel.org/r/20260120124005.148381-1-me@linux.beauty Fixes: 8652d44f466a ("kexec: support purgatories with .text.hot sections") Signed-off-by: Li Chen Acked-by: Baoquan He Cc: Alexander Graf Cc: Eric Biggers Cc: Li Chen Cc: Philipp Rudo Cc: Ricardo Ribalda Delgado Cc: Ross Zwisler Cc: Sourabh Jain Cc: Steven Rostedt Cc: Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

tracing: Fix false sharing in hwlat get_sample()

2026-03-04T12:20:31Z

[ Upstream commit f743435f988cb0cf1f521035aee857851b25e06d ] The get_sample() function in the hwlat tracer assumes the caller holds hwlat_data.lock, but this is not actually happening. The result is unprotected data access to hwlat_data, and in per-cpu mode can result in false sharing which may show up as false positive latency events. The specific case of false sharing observed was primarily between hwlat_data.sample_width and hwlat_data.count. These are separated by just 8B and are therefore likely to share a cache line. When one thread modifies count, the cache line is in a modified state so when other threads read sample_width in the main latency detection loop, they fetch the modified cache line. On some systems, the fetch itself may be slow enough to count as a latency event, which could set up a self reinforcing cycle of latency events as each event increments count which then causes more latency events, continuing the cycle. The other result of the unprotected data access is that hwlat_data.count can end up with duplicate or missed values, which was observed on some systems in testing. Convert hwlat_data.count to atomic64_t so it can be safely modified without locking, and prevent false sharing by pulling sample_width into a local variable. One system this was tested on was a dual socket server with 32 CPUs on each numa node. With settings of 1us threshold, 1000us width, and 2000us window, this change reduced the number of latency events from 500 per second down to approximately 1 event per minute. Some machines tested did not exhibit measurable latency from the false sharing. Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Link: https://patch.msgid.link/20260210074810.6328-1-clord@mykolab.com Signed-off-by: Colin Lord Signed-off-by: Steven Rostedt (Google) Signed-off-by: Sasha Levin

bpf: verifier improvement in 32bit shift sign extension pattern

2026-03-04T12:20:16Z

[ Upstream commit d18dec4b8990048ce75f0ece32bb96b3fbd3f422 ] This patch improves the verifier to correctly compute bounds for sign extension compiler pattern composed of left shift by 32bits followed by a sign right shift by 32bits. Pattern in the verifier was limitted to positive value bounds and would reset bound computation for negative values. New code allows both positive and negative values for sign extension without compromising bound computation and verifier to pass. This change is required by GCC which generate such pattern, and was detected in the context of systemd, as described in the following GCC bugzilla: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119731 Three new tests were added in verifier_subreg.c. Signed-off-by: Cupertino Miranda Signed-off-by: Andrew Pinski Acked-by: Eduard Zingerman Cc: David Faust Cc: Jose Marchesi Cc: Elena Zannoni Link: https://lore.kernel.org/r/20251202180220.11128-2-cupertino.miranda@oracle.com Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin

tracing: Remove duplicate ENABLE_EVENT_STR and DISABLE_EVENT_STR macros

2026-03-04T12:19:54Z

[ Upstream commit 9df0e49c5b9b8d051529be9994e4f92f2d20be6f ] The macros ENABLE_EVENT_STR and DISABLE_EVENT_STR were added to trace.h so that more than one file can have access to them, but was never removed from their original location. Remove the duplicates. Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Tom Zanussi Link: https://patch.msgid.link/20260126130037.4ba201f9@gandalf.local.home Fixes: d0bad49bb0a09 ("tracing: Add enable_hist/disable_hist triggers") Signed-off-by: Steven Rostedt (Google) Signed-off-by: Sasha Levin

tracing: Properly process error handling in event_hist_trigger_parse()

2026-03-04T12:19:54Z

[ Upstream commit 0550069cc25f513ce1f109c88f7c1f01d63297db ] Memory allocated with trigger_data_alloc() requires trigger_data_free() for proper cleanup. Replace kfree() with trigger_data_free() to fix this. Found via static analysis and code review. This isn't a real bug due to the current code basically being an open coded version of trigger_data_free() without the synchronization. The synchronization isn't needed as this is the error path of creation and there's nothing to synchronize against yet. Replace the kfree() to be consistent with the allocation. Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Tom Zanussi Link: https://patch.msgid.link/20251211100058.2381268-1-linmq006@gmail.com Fixes: e1f187d09e11 ("tracing: Have existing event_command.parse() implementations use helpers") Signed-off-by: Miaoqian Lin Signed-off-by: Steven Rostedt (Google) Signed-off-by: Sasha Levin

timers: Replace in_irq() with in_hardirq()

2026-03-04T12:19:43Z

[ Upstream commit 8be3f96ceddb911539a53d87a66da84a04502366 ] Replace the obsolete and ambiguous macro in_irq() with new macro in_hardirq(). Signed-off-by: ye xingchen Signed-off-by: Thomas Gleixner Acked-by: John Stultz Link: https://lore.kernel.org/r/20221012012629.334966-1-ye.xingchen@zte.com.cn Stable-dep-of: c9efde1e537b ("nfc: hci: shdlc: Stop timers and work before freeing context") Signed-off-by: Sasha Levin

ucount: check for CAP_SYS_RESOURCE using ns_capable_noaudit()

2026-03-04T12:19:42Z

[ Upstream commit 0895a000e4fff9e950a7894210db45973e485c35 ] The user.* sysctls implement the ctl_table_root::permissions hook and they override the file access mode based on the CAP_SYS_RESOURCE capability (at most rwx if capable, at most r-- if not). The capability is being checked unconditionally, so if an LSM denies the capability, an audit record may be logged even when access is in fact granted. Given the logic in the set_permissions() function in kernel/ucount.c and the unfortunate way the permission checking is implemented, it doesn't seem viable to avoid false positive denials by deferring the capability check. Thus, do the same as in net_ctl_permissions() (net/sysctl_net.c) - switch from ns_capable() to ns_capable_noaudit(), so that the check never logs an audit record. Link: https://lkml.kernel.org/r/20260122140745.239428-1-omosnace@redhat.com Fixes: dbec28460a89 ("userns: Add per user namespace sysctls.") Signed-off-by: Ondrej Mosnacek Reviewed-by: Paul Moore Acked-by: Serge Hallyn Cc: Eric Biederman Cc: Alexey Gladkov Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

kallsyms/ftrace: set module buildid in ftrace_mod_address_lookup()

2026-03-04T12:19:40Z

[ Upstream commit e8a1e7eaa19d0b757b06a2f913e3eeb4b1c002c6 ] __sprint_symbol() might access an invalid pointer when kallsyms_lookup_buildid() returns a symbol found by ftrace_mod_address_lookup(). The ftrace lookup function must set both @modname and @modbuildid the same way as module_address_lookup(). Link: https://lkml.kernel.org/r/20251128135920.217303-7-pmladek@suse.com Fixes: 9294523e3768 ("module: add printk formats to add module build ID to stacktraces") Signed-off-by: Petr Mladek Reviewed-by: Aaron Tomlin Acked-by: Steven Rostedt (Google) Cc: Alexei Starovoitov Cc: Daniel Borkman Cc: Daniel Gomez Cc: John Fastabend Cc: Kees Cook Cc: Luis Chamberalin Cc: Marc Rutland Cc: "Masami Hiramatsu (Google)" Cc: Petr Pavlu Cc: Sami Tolvanen Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

module: add helper function for reading module_buildid()

2026-03-04T12:19:40Z

[ Upstream commit acfdbb4ab2910ff6f03becb569c23ac7b2223913 ] Add a helper function for reading the optional "build_id" member of struct module. It is going to be used also in ftrace_mod_address_lookup(). Use "#ifdef" instead of "#if IS_ENABLED()" to match the declaration of the optional field in struct module. Link: https://lkml.kernel.org/r/20251128135920.217303-4-pmladek@suse.com Signed-off-by: Petr Mladek Reviewed-by: Daniel Gomez Reviewed-by: Petr Pavlu Cc: Aaron Tomlin Cc: Alexei Starovoitov Cc: Daniel Borkman Cc: John Fastabend Cc: Kees Cook Cc: Luis Chamberalin Cc: Marc Rutland Cc: "Masami Hiramatsu (Google)" Cc: Sami Tolvanen Cc: Steven Rostedt (Google) Signed-off-by: Andrew Morton Stable-dep-of: e8a1e7eaa19d ("kallsyms/ftrace: set module buildid in ftrace_mod_address_lookup()") Signed-off-by: Sasha Levin