kernel.git/lib, branch linux-6.12.y

Remove WARN_ALL_UNSEEDED_RANDOM kernel config option

2026-03-04T12:21:32Z

[ Upstream commit 7dff99b354601dd01829e1511711846e04340a69 ] This config option goes way back - it used to be an internal debug option to random.c (at that point called DEBUG_RANDOM_BOOT), then was renamed and exposed as a config option as CONFIG_WARN_UNSEEDED_RANDOM, and then further renamed to the current CONFIG_WARN_ALL_UNSEEDED_RANDOM. It was all done with the best of intentions: the more limited rate-limited reports were reporting some cases, but if you wanted to see all the gory details, you'd enable this "ALL" option. However, it turns out - perhaps not surprisingly - that when people don't care about and fix the first rate-limited cases, they most certainly don't care about any others either, and so warning about all of them isn't actually helping anything. And the non-ratelimited reporting causes problems, where well-meaning people enable debug options, but the excessive flood of messages that nobody cares about will hide actual real information when things go wrong. I just got a kernel bug report (which had nothing to do with randomness) where two thirds of the the truncated dmesg was just variations of random: get_random_u32 called from __get_random_u32_below+0x10/0x70 with crng_init=0 and in the process early boot messages had been lost (in addition to making the messages that _hadn't_ been lost harder to read). The proper way to find these things for the hypothetical developer that cares - if such a person exists - is almost certainly with boot time tracing. That gives you the option to get call graphs etc too, which is likely a requirement for fixing any problems anyway. See Documentation/trace/boottime-trace.rst for that option. And if we for some reason do want to re-introduce actual printing of these things, it will need to have some uniqueness filtering rather than this "just print it all" model. Fixes: cc1e127bfa95 ("random: remove ratelimiting for in-kernel unseeded randomness") Acked-by: Jason Donenfeld Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

objpool: fix the overestimation of object pooling metadata size

2026-03-04T12:20:35Z

[ Upstream commit 5ed4b6b37c647d168ae31035b3f61b705997e043 ] objpool uses struct objpool_head to store metadata information, and its cpu_slots member points to an array of pointers that store the addresses of the percpu ring arrays. However, the memory size allocated during the initialization of cpu_slots is nr_cpu_ids * sizeof(struct objpool_slot). On a 64-bit machine, the size of struct objpool_slot is 16 bytes, which is twice the size of the actual pointer required, and the extra memory is never be used, resulting in a waste of memory. Therefore, the memory size required for cpu_slots needs to be corrected. Link: https://lkml.kernel.org/r/20260202132846.68257-1-zhouwenhao7600@gmail.com Fixes: b4edb8d2d464 ("lib: objpool added: ring-array based lockless MPMC") Signed-off-by: zhouwenhao Reviewed-by: Andrew Morton Cc: "Masami Hiramatsu (Google)" Cc: Matt Wu Cc: wuqiang.matt Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

procfs: avoid fetching build ID while holding VMA lock

2026-02-11T12:40:18Z

[ Upstream commit b5cbacd7f86f4f62b8813688c8e73be94e8e1951 ] Fix PROCMAP_QUERY to fetch optional build ID only after dropping mmap_lock or per-VMA lock, whichever was used to lock VMA under question, to avoid deadlock reported by syzbot: -> #1 (&mm->mmap_lock){++++}-{4:4}: __might_fault+0xed/0x170 _copy_to_iter+0x118/0x1720 copy_page_to_iter+0x12d/0x1e0 filemap_read+0x720/0x10a0 blkdev_read_iter+0x2b5/0x4e0 vfs_read+0x7f4/0xae0 ksys_read+0x12a/0x250 do_syscall_64+0xcb/0xf80 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&sb->s_type->i_mutex_key#8){++++}-{4:4}: __lock_acquire+0x1509/0x26d0 lock_acquire+0x185/0x340 down_read+0x98/0x490 blkdev_read_iter+0x2a7/0x4e0 __kernel_read+0x39a/0xa90 freader_fetch+0x1d5/0xa80 __build_id_parse.isra.0+0xea/0x6a0 do_procmap_query+0xd75/0x1050 procfs_procmap_ioctl+0x7a/0xb0 __x64_sys_ioctl+0x18e/0x210 do_syscall_64+0xcb/0xf80 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(&mm->mmap_lock); lock(&sb->s_type->i_mutex_key#8); lock(&mm->mmap_lock); rlock(&sb->s_type->i_mutex_key#8); *** DEADLOCK *** This seems to be exacerbated (as we haven't seen these syzbot reports before that) by the recent: 777a8560fd29 ("lib/buildid: use __kernel_read() for sleepable context") To make this safe, we need to grab file refcount while VMA is still locked, but other than that everything is pretty straightforward. Internal build_id_parse() API assumes VMA is passed, but it only needs the underlying file reference, so just add another variant build_id_parse_file() that expects file passed directly. [akpm@linux-foundation.org: fix up kerneldoc] Link: https://lkml.kernel.org/r/20260129215340.3742283-1-andrii@kernel.org Fixes: ed5d583a88a9 ("fs/procfs: implement efficient VMA querying API for /proc//maps") Signed-off-by: Andrii Nakryiko Reported-by: Reviewed-by: Suren Baghdasaryan Tested-by: Suren Baghdasaryan Reviewed-by: Shakeel Butt Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Eduard Zingerman Cc: Hao Luo Cc: Jiri Olsa Cc: John Fastabend Cc: KP Singh Cc: Martin KaFai Lau Cc: Song Liu Cc: Stanislav Fomichev Cc: Yonghong Song Cc: Signed-off-by: Andrew Morton [ mm is local var instead of function param ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

flex_proportions: make fprop_new_period() hardirq safe

2026-02-06T15:55:46Z

commit dd9e2f5b38f1fdd49b1ab6d3a85f81c14369eacc upstream. Bernd has reported a lockdep splat from flexible proportions code that is essentially complaining about the following race: run_timer_softirq - we are in softirq context call_timer_fn writeout_period fprop_new_period write_seqcount_begin(&p->sequence); ... blk_mq_end_request() blk_update_request() ext4_end_bio() folio_end_writeback() __wb_writeout_add() __fprop_add_percpu_max() if (unlikely(max_frac < FPROP_FRAC_BASE)) { fprop_fraction_percpu() seq = read_seqcount_begin(&p->sequence); - sees odd sequence so loops indefinitely Note that a deadlock like this is only possible if the bdi has configured maximum fraction of writeout throughput which is very rare in general but frequent for example for FUSE bdis. To fix this problem we have to make sure write section of the sequence counter is irqsafe. Link: https://lkml.kernel.org/r/20260121112729.24463-2-jack@suse.cz Fixes: a91befde3503 ("lib/flex_proportions.c: remove local_irq_ops in fprop_new_period()") Signed-off-by: Jan Kara Reported-by: Bernd Schubert Link: https://lore.kernel.org/all/9b845a47-9aee-43dd-99bc-1a82bea00442@bsbernd.com/ Reviewed-by: Matthew Wilcox (Oracle) Cc: Joanne Koong Cc: Miklos Szeredi Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

lib/buildid: use __kernel_read() for sleepable context

2026-01-23T10:18:43Z

commit 777a8560fd29738350c5094d4166fe5499452409 upstream. 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 Reviewed-by: Christoph Hellwig Tested-by: Jinchao Wang Link: https://lkml.kernel.org/r/aUteBPWPYzVWIZFH@ndev Reviewed-by: Christian Brauner Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Daniel Borkman Cc: "Darrick J. Wong" Cc: Matthew Wilcox (Oracle) Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

lib/crypto: aes: Fix missing MMU protection for AES S-box

2026-01-17T15:31:16Z

commit 74d74bb78aeccc9edc10db216d6be121cf7ec176 upstream. __cacheline_aligned puts the data in the ".data..cacheline_aligned" section, which isn't marked read-only i.e. it doesn't receive MMU protection. Replace it with ____cacheline_aligned which does the right thing and just aligns the data while keeping it in ".rodata". Fixes: b5e0b032b6c3 ("crypto: aes - add generic time invariant AES cipher") Cc: stable@vger.kernel.org Reported-by: Qingfang Deng Closes: https://lore.kernel.org/r/20260105074712.498-1-dqfext@gmail.com/ Acked-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20260107052023.174620-1-ebiggers@kernel.org Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman

idr: fix idr_alloc() returning an ID out of range

2026-01-08T09:14:50Z

commit c6e8e595a0798ad67da0f7bebaf69c31ef70dfff upstream. If you use an IDR with a non-zero base, and specify a range that lies entirely below the base, 'max - base' becomes very large and idr_get_free() can return an ID that lies outside of the requested range. Link: https://lkml.kernel.org/r/20251128161853.3200058-1-willy@infradead.org Fixes: 6ce711f27500 ("idr: Make 1-based IDRs more efficient") Signed-off-by: Matthew Wilcox (Oracle) Reported-by: Jan Sokolowski Reported-by: Koen Koning Reported-by: Peter Senna Tschudin Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/6449 Reviewed-by: Christian König Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

lib/vsprintf: Check pointer before dereferencing in time_and_date()

2025-12-18T12:54:57Z

[ Upstream commit 372a12bd5df0199aa234eaf8ef31ed7ecd61d40f ] The pointer may be invalid when gets to the printf(). In particular the time_and_date() dereferencing it in some cases without checking. Move the check from rtc_str() to time_and_date() to cover all cases. Fixes: 7daac5b2fdf8 ("lib/vsprintf: Print time64_t in human readable format") Signed-off-by: Andy Shevchenko Reviewed-by: Petr Mladek Link: https://patch.msgid.link/20251110132118.4113976-1-andriy.shevchenko@linux.intel.com Signed-off-by: Petr Mladek Signed-off-by: Sasha Levin

maple_tree: fix tracepoint string pointers

2025-12-01T10:43:39Z

commit 91a54090026f84ceffaa12ac53c99b9f162946f6 upstream. maple_tree tracepoints contain pointers to function names. Such a pointer is saved when a tracepoint logs an event. There's no guarantee that it's still valid when the event is parsed later and the pointer is dereferenced. The kernel warns about these unsafe pointers. event 'ma_read' has unsafe pointer field 'fn' WARNING: kernel/trace/trace.c:3779 at ignore_event+0x1da/0x1e4 Mark the function names as tracepoint_string() to fix the events. One case that doesn't work without my patch would be trace-cmd record to save the binary ringbuffer and trace-cmd report to parse it in userspace. The address of __func__ can't be dereferenced from userspace but tracepoint_string will add an entry to /sys/kernel/tracing/printk_formats Link: https://lkml.kernel.org/r/20251030155537.87972-1-martin@kaiser.cx Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Martin Kaiser Acked-by: Liam R. Howlett Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

lib/crypto: curve25519-hacl64: Fix older clang KASAN workaround for GCC

2025-11-13T20:34:40Z

commit 2b81082ad37cc3f28355fb73a6a69b91ff7dbf20 upstream. Commit 2f13daee2a72 ("lib/crypto/curve25519-hacl64: Disable KASAN with clang-17 and older") inadvertently disabled KASAN in curve25519-hacl64.o for GCC unconditionally because clang-min-version will always evaluate to nothing for GCC. Add a check for CONFIG_CC_IS_CLANG to avoid applying the workaround for GCC, which is only needed for clang-17 and older. Cc: stable@vger.kernel.org Fixes: 2f13daee2a72 ("lib/crypto/curve25519-hacl64: Disable KASAN with clang-17 and older") Signed-off-by: Nathan Chancellor Acked-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20251103-curve25519-hacl64-fix-kasan-workaround-v2-1-ab581cbd8035@kernel.org Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman