kernel/git/stable/linux.git/lib, branch linux-6.6.y

debugobjects: Dont call fill_pool() in early boot hardirq context

2026-07-04T11:42:18+00:00

commit 0d046ae106255cba5eb83b23f78ee93f3620247d upstream. When booting a debug PREEMPT_RT kernel on an ARM64 system, a "inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage" lockdep warning message was reported to the console. During early boot, interrupts are enabled before the scheduler is enabled. In this window (before SYSTEM_SCHEDULING is set) interrupts can fire and in the hard interrupt context handler attempt to fill the pool This can lead to a deadlock when the interrupt occurred when the interrupt hits a region which holds a lock that is required to be taken in the allocation path. Add a new can_fill_pool() helper and reorder the exception rule and forbid this scenario by excluding allocations from hard interrupt context. Fixes: 06e0ae988f6e ("debugobjects: Allow to refill the pool before SYSTEM_SCHEDULING") Suggested-by: Sebastian Andrzej Siewior Suggested-by: Thomas Gleixner Signed-off-by: Waiman Long Signed-off-by: Thomas Gleixner Reviewed-by: Sebastian Andrzej Siewior Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260605173038.495075-1-longman@redhat.com Signed-off-by: Sasha Levin

debugobjects: Do not fill_pool() if pi_blocked_on

2026-07-04T11:42:18+00:00

commit 5f41161059fd0f1bbf18c90f3180e38cc45a14eb upstream. On RT enabled kernels, fill_pool() ends up calling rtlock_lock(), which asserts if current::pi_blocked_on is set, because a task can obviously only block on one lock as otherwise the priority inheritenace chain gets corrupted. Prevent this by expanding the conditional to take current::pi_blocked_on into account. Fixes: 4bedcc28469a ("debugobjects: Make them PREEMPT_RT aware") Reported-by: syzbot+b8ca586b9fc235f0c0df@syzkaller.appspotmail.com Signed-off-by: Helen Koike Signed-off-by: Thomas Gleixner Link: https://patch.msgid.link/20260511215359.3351259-1-koike@igalia.com Closes: https://syzkaller.appspot.com/bug?extid=b8ca586b9fc235f0c0df Signed-off-by: Sasha Levin

debugobjects: Use LD_WAIT_CONFIG instead of LD_WAIT_SLEEP

2026-07-04T11:42:18+00:00

commit 37de2dbc318ee10577c1c2704de5a803e75e55a2 upstream. fill_pool_map is used to suppress nesting violations caused by acquiring a spinlock_t (from within the memory allocator) while holding a raw_spinlock_t. The used annotation is wrong. LD_WAIT_SLEEP is for always sleeping lock types such as mutex_t. LD_WAIT_CONFIG is for lock type which are sleeping while spinning on PREEMPT_RT such as spinlock_t. Use LD_WAIT_CONFIG as override. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Link: https://patch.msgid.link/20251127153652.291697-3-bigeasy@linutronix.de Signed-off-by: Sasha Levin

debugobjects: Allow to refill the pool before SYSTEM_SCHEDULING

2026-07-04T11:42:18+00:00

commit 06e0ae988f6e3499785c407429953ade19c1096b upstream. The pool of free objects is refilled on several occasions such as object initialisation. On PREEMPT_RT refilling is limited to preemptible sections due to sleeping locks used by the memory allocator. The system boots with disabled interrupts so the pool can not be refilled. If too many objects are initialized and the pool gets empty then debugobjects disables itself. Refiling can also happen early in the boot with disabled interrupts as long as the scheduler is not operational. If the scheduler can not preempt a task then a sleeping lock can not be contended. Allow to additionally refill the pool if the scheduler is not operational. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Link: https://patch.msgid.link/20251127153652.291697-2-bigeasy@linutronix.de Signed-off-by: Sasha Levin

iommu, debugobjects: avoid gcc-16.1 section mismatch warnings

2026-06-19T11:39:19+00:00

commit 4c9ad387aa2d6785299722e54224d34764edaeb3 upstream. gcc-16 has gained some more advanced inter-procedual optimization techniques that enable it to inline the dummy_tlb_add_page() and dummy_tlb_flush() function pointers into a specialized version of __arm_v7s_unmap: WARNING: modpost: vmlinux: section mismatch in reference: __arm_v7s_unmap+0x2cc (section: .text) -> dummy_tlb_add_page (section: .init.text) ERROR: modpost: Section mismatches detected. >From what I can tell, the transformation is correct, as this is only called when __arm_v7s_unmap() is called from arm_v7s_do_selftests(), which is also __init. Since __arm_v7s_unmap() however is not __init, gcc cannot inline the inner function calls directly. In debug_objects_selftest(), the same thing happens. Both the caller and the leaf function are __init, but the IPA pulls it into a non-init one: WARNING: modpost: vmlinux: section mismatch in reference: lookup_object_or_alloc+0x7c (section: .text.lookup_object_or_alloc) -> is_static_object (section: .init.text) Marking the affected functions as not "__init" would reliably avoid this issue but is not a good solution because it removes an otherwise correct annotation. I tried marking the functions as 'noinline', but that ended up not covering all the affected configurations. With some more experimenting, I found that marking these functions as __attribute__((noipa)) is both logical and reliable. In order to keep the syntax readable, add a custom macro for this in include/linux/compiler_attributes.h next to other related macros and use it to annotate both files. Link: https://lore.kernel.org/all/abRB6g-48ZX6Yl2r@willie-the-truck/ Cc: Will Deacon Cc: Thomas Gleixner Cc: Andrew Morton Cc: Miguel Ojeda Cc: linux-kbuild@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by: Arnd Bergmann Acked-by: Will Deacon Acked-by: Thomas Gleixner Acked-by: Miguel Ojeda Signed-off-by: Joerg Roedel Signed-off-by: Greg Kroah-Hartman

test_kprobes: clear kprobes between test runs

2026-06-01T15:43:11+00:00

[ Upstream commit ef5581bb30efb939cc2bf093475c6cc85258e5cd ] Running the kprobes sanity tests twice makes all tests fail and eventually crashes the kernel. [root@martin-riscv-1 ~]# echo 1 > /sys/kernel/debug/kunit/kprobes_test/run ... # Totals: pass:5 fail:0 skip:0 total:5 ok 1 kprobes_test [root@martin-riscv-1 ~]# echo 1 > /sys/kernel/debug/kunit/kprobes_test/run ... # test_kprobe: EXPECTATION FAILED at lib/tests/test_kprobes.c:64 Expected 0 == register_kprobe(&kp), but register_kprobe(&kp) == -22 (0xffffffffffffffea) ... Unable to handle kernel paging request ... The testsuite defines several kprobes and kretprobes as static variables that are preserved across test runs. After register_kprobe and unregister_kprobe, a kprobe contains some leftover data that must be cleared before the kprobe can be registered again. The tests are setting symbol_name to define the probe location. Address and flags must be cleared. The existing code clears some of the probes between subsequent tests, but not between two test runs. The leftover data from a previous test run makes the registrations fail in the next run. Move the cleanups for all kprobes into kprobes_test_init, this function is called before each single test (including the first test of a test run). Link: https://lore.kernel.org/all/20260507134615.1010905-1-martin@kaiser.cx/ Fixes: e44e81c5b90f ("kprobes: convert tests to kunit") Signed-off-by: Martin Kaiser Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Sasha Levin

kunit: config: KUNIT_DEBUGFS should depend on DEBUG_FS

2026-06-01T15:43:11+00:00

[ Upstream commit 8f80b5b227ef9ea422080487715c841856339aed ] CONFIG_KUNIT_DEBUGFS is totally useless without debugfs, so it should depend on CONFIG_DEBUG_FS. Link: https://lore.kernel.org/r/20260425034155.53913-2-david@davidgow.net Fixes: e2219db280e3 ("kunit: add debugfs /sys/kernel/debug/kunit//results display") Signed-off-by: David Gow Signed-off-by: Shuah Khan Signed-off-by: Sasha Levin

kunit: config: Enable KUNIT_DEBUGFS by default

2026-06-01T15:43:11+00:00

[ Upstream commit 17e4c68ff35090d8cb743e3c82c09f92fda1ebda ] The KUNIT_DEBUGFS option is currently enabled based on the value of KUNIT_ALL_TESTS, but it really doesn't have anything to do with the set of enabled tests, so just enable it by default anyway. In particular, this shouldn't be only visible if KUNIT_ALL_TESTS is set, which is quite confusing. Link: https://lore.kernel.org/r/20260425034155.53913-1-david@davidgow.net Fixes: beaed42c427d ("kunit: default KUNIT_* fragments to KUNIT_ALL_TESTS") Signed-off-by: David Gow Signed-off-by: Shuah Khan Signed-off-by: Sasha Levin

lib: test_hmm: evict device pages on file close to avoid use-after-free

2026-05-17T15:13:48+00:00

[ Upstream commit 744dd97752ef1076a8d8672bb0d8aa2c7abc1144 ] Patch series "Minor hmm_test fixes and cleanups". Two bugfixes a cleanup for the HMM kernel selftests. These were mostly reported by Zenghui Yu with special thanks to Lorenzo for analysing and pointing out the problems. This patch (of 3): When dmirror_fops_release() is called it frees the dmirror struct but doesn't migrate device private pages back to system memory first. This leaves those pages with a dangling zone_device_data pointer to the freed dmirror. If a subsequent fault occurs on those pages (eg. during coredump) the dmirror_devmem_fault() callback dereferences the stale pointer causing a kernel panic. This was reported [1] when running mm/ksft_hmm.sh on arm64, where a test failure triggered SIGABRT and the resulting coredump walked the VMAs faulting in the stale device private pages. Fix this by calling dmirror_device_evict_chunk() for each devmem chunk in dmirror_fops_release() to migrate all device private pages back to system memory before freeing the dmirror struct. The function is moved earlier in the file to avoid a forward declaration. Link: https://lore.kernel.org/20260331063445.3551404-1-apopple@nvidia.com Link: https://lore.kernel.org/20260331063445.3551404-2-apopple@nvidia.com Fixes: b2ef9f5a5cb3 ("mm/hmm/test: add selftest driver for HMM") Signed-off-by: Alistair Popple Reported-by: Zenghui Yu Closes: https://lore.kernel.org/linux-mm/8bd0396a-8997-4d2e-a13f-5aac033083d7@linux.dev/ Reviewed-by: Balbir Singh Tested-by: Zenghui Yu Cc: David Hildenbrand Cc: Jason Gunthorpe Cc: Leon Romanovsky Cc: Liam Howlett Cc: Lorenzo Stoakes (Oracle) Cc: Michal Hocko Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Zenghui Yu Cc: Matthew Brost Cc: Signed-off-by: Andrew Morton [ kept the existing simpler `dmirror_device_evict_chunk()` body instead of the upstream compound-folio version ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

lib/scatterlist: fix temp buffer in extract_user_to_sg()

2026-05-17T15:13:41+00:00

commit 118cf3f55975352ac357fb194405031458186819 upstream. Instead of allocating a temporary buffer for extracted user pages extract_user_to_sg() uses the end of the to be filled scatterlist as a temporary buffer. Fix the calculation of the start address if the scatterlist already contains elements. The unused space starts at sgtable->sgl + sgtable->nents not directly at sgtable->nents and the temporary buffer is placed at the end of this unused space. A subsequent commit will add kunit test cases that demonstrate that the patch is necessary. Pointed out by sashiko.dev on a previous iteration of this series. Link: https://lkml.kernel.org/r/20260326214905.818170-3-lk@c--e.de Fixes: 018584697533 ("netfs: Add a function to extract an iterator into a scatterlist") Signed-off-by: Christian A. Ehrhardt Cc: David Howells Cc: David Gow Cc: Kees Cook Cc: Petr Mladek Cc: [v6.5+] Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman