- 03 Jun, 2019 26 commits
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Imre Deak authored
The sequence static DEFINE_WW_CLASS(test_ww_class); struct ww_acquire_ctx ww_ctx; struct ww_mutex ww_lock_a; struct ww_mutex ww_lock_b; struct ww_mutex ww_lock_c; struct mutex lock_c; ww_acquire_init(&ww_ctx, &test_ww_class); ww_mutex_init(&ww_lock_a, &test_ww_class); ww_mutex_init(&ww_lock_b, &test_ww_class); ww_mutex_init(&ww_lock_c, &test_ww_class); mutex_init(&lock_c); ww_mutex_lock(&ww_lock_a, &ww_ctx); mutex_lock(&lock_c); ww_mutex_lock(&ww_lock_b, &ww_ctx); ww_mutex_lock(&ww_lock_c, &ww_ctx); mutex_unlock(&lock_c); (*) ww_mutex_unlock(&ww_lock_c); ww_mutex_unlock(&ww_lock_b); ww_mutex_unlock(&ww_lock_a); ww_acquire_fini(&ww_ctx); (**) will trigger the following error in __lock_release() when calling mutex_release() at **: DEBUG_LOCKS_WARN_ON(depth <= 0) The problem is that the hlock merging happening at * updates the references for test_ww_class incorrectly to 3 whereas it should've updated it to 4 (representing all the instances for ww_ctx and ww_lock_[abc]). Fix this by updating the references during merging correctly taking into account that we can have non-zero references (both for the hlock that we merge into another hlock or for the hlock we are merging into). Signed-off-by:
Imre Deak <imre.deak@intel.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Cc: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: https://lkml.kernel.org/r/20190524201509.9199-2-imre.deak@intel.comSigned-off-by:
Ingo Molnar <mingo@kernel.org>
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Imre Deak authored
The sequence static DEFINE_WW_CLASS(test_ww_class); struct ww_acquire_ctx ww_ctx; struct ww_mutex ww_lock_a; struct ww_mutex ww_lock_b; struct mutex lock_c; struct mutex lock_d; ww_acquire_init(&ww_ctx, &test_ww_class); ww_mutex_init(&ww_lock_a, &test_ww_class); ww_mutex_init(&ww_lock_b, &test_ww_class); mutex_init(&lock_c); ww_mutex_lock(&ww_lock_a, &ww_ctx); mutex_lock(&lock_c); ww_mutex_lock(&ww_lock_b, &ww_ctx); mutex_unlock(&lock_c); (*) ww_mutex_unlock(&ww_lock_b); ww_mutex_unlock(&ww_lock_a); ww_acquire_fini(&ww_ctx); triggers the following WARN in __lock_release() when doing the unlock at *: DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1); The problem is that the WARN check doesn't take into account the merging of ww_lock_a and ww_lock_b which results in decreasing curr->lockdep_depth by 2 not only 1. Note that the following sequence doesn't trigger the WARN, since there won't be any hlock merging. ww_acquire_init(&ww_ctx, &test_ww_class); ww_mutex_init(&ww_lock_a, &test_ww_class); ww_mutex_init(&ww_lock_b, &test_ww_class); mutex_init(&lock_c); mutex_init(&lock_d); ww_mutex_lock(&ww_lock_a, &ww_ctx); mutex_lock(&lock_c); mutex_lock(&lock_d); ww_mutex_lock(&ww_lock_b, &ww_ctx); mutex_unlock(&lock_d); ww_mutex_unlock(&ww_lock_b); ww_mutex_unlock(&ww_lock_a); mutex_unlock(&lock_c); ww_acquire_fini(&ww_ctx); In general both of the above two sequences are valid and shouldn't trigger any lockdep warning. Fix this by taking the decrement due to the hlock merging into account during lock release and hlock class re-setting. Merging can't happen during lock downgrading since there won't be a new possibility to merge hlocks in that case, so add a WARN if merging still happens then. Signed-off-by:
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Yuyang Du authored
In mark_lock_irq(), the following checks are performed: ---------------------------------- | -> | unsafe | read unsafe | |----------------------------------| | safe | F B | F* B* | |----------------------------------| | read safe | F? B* | - | ---------------------------------- Where: F: check_usage_forwards B: check_usage_backwards *: check enabled by STRICT_READ_CHECKS ?: check enabled by the !dir condition From checking point of view, the special F? case does not make sense, whereas it perhaps is made for peroformance concern. As later patch will address this issue, remove this exception, which makes the checks consistent later. With STRICT_READ_CHECKS = 1 which is default, there is no functional change. Signed-off-by:
Yuyang Du <duyuyang@gmail.com> Signed-off-by:
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Yuyang Du authored
The new bit can be any possible lock usage except it is garbage, so the cases in switch can be made simpler. Warn early on if wrong usage bit is passed without taking locks. No functional change. Signed-off-by:
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Yuyang Du authored
Lock usage bit initialization is consolidated into one function mark_usage(). Trivial readability improvement. No functional change. Signed-off-by:
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Yuyang Du authored
As Peter has put it all sound and complete for the cause, I simply quote: "It (check_redundant) was added for cross-release (which has since been reverted) which would generate a lot of redundant links (IIRC) but having it makes the reports more convoluted -- basically, if we had an A-B-C relation, then A-C will not be added to the graph because it is already covered. This then means any report will include B, even though a shorter cycle might have been possible." This would increase the number of direct dependencies. For a simple workload (make clean; reboot; make vmlinux -j8), the data looks like this: CONFIG_LOCKDEP_SMALL: direct dependencies: 6926 !CONFIG_LOCKDEP_SMALL: direct dependencies: 9052 (+30.7%) Suggested-by:
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Yuyang Du authored
These two functions now handle different check results themselves. A new check_path function is added to check whether there is a path in the dependency graph. No functional change. Signed-off-by:
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Yuyang Du authored
The @nested is not used in __release_lock so remove it despite that it is not used in lock_release in the first place. Signed-off-by:
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Yuyang Du authored
In check_deadlock(), the third argument read comes from the second argument hlock so that it can be removed. No functional change. Signed-off-by:
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Yuyang Du authored
The irq usage and lock dependency rules that if violated a deacklock may happen are explained in more detail. Signed-off-by:
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Yuyang Du authored
The breadth-first search is implemented as flat-out non-recursive now, but the comments are still describing it as recursive, update the comments in that regard. Signed-off-by:
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Yuyang Du authored
In search of a dependency in the lock graph, there is contant checks for forward or backward search. Directly reference the field offset of the struct that differentiates the type of search to avoid those checks. No functional change. Signed-off-by:
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Yuyang Du authored
With the change, we can slightly adjust the code to iterate the queue in BFS search, which simplifies the code. No functional change. Signed-off-by:
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Yuyang Du authored
The element field is an array in struct circular_queue to keep track of locks in the search. Making it the same type as the locks avoids type cast. Also fix a typo and elaborate the comment above struct circular_queue. No functional change. Signed-off-by:
Bart Van Assche <bvanassche@acm.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: frederic@kernel.org Cc: ming.lei@redhat.com Cc: will.deacon@arm.com Link: https://lkml.kernel.org/r/20190506081939.74287-13-duyuyang@gmail.comSigned-off-by:
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Yuyang Du authored
A leftover comment is removed. While at it, add more explanatory comments. Such a trivial patch! Signed-off-by:
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Yuyang Du authored
The lockdep_map argument in them is not used, remove it. Signed-off-by:
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Yuyang Du authored
held_lock->class_idx is used to point to the class of the held lock. The index is shifted by 1 to make index 0 mean no class, which results in class index shifting back and forth but is not worth doing so. The reason is: (1) there will be no "no-class" held_lock to begin with, and (2) index 0 seems to be used for error checking, but if something wrong indeed happened, the index can't be counted on to distinguish it as that something won't set the class_idx to 0 on purpose to tell us it is wrong. Therefore, change the index to start from 0. This saves a lot of back-and-forth shifts and a class slot back to lock_classes. Since index 0 is now used for lock class, we change the initial chain key to -1 to avoid key collision, which is due to the fact that __jhash_mix(0, 0, 0) = 0. Actually, the initial chain key can be any arbitrary value other than 0. In addition, a bitmap is maintained to keep track of the used lock classes, and we check the validity of the held lock against that bitmap. Signed-off-by:
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Yuyang Du authored
Chain keys are computed using Jenkins hash function, which needs an initial hash to start with. Dedicate a macro to make this clear and configurable. A later patch changes this initial chain key. Signed-off-by:
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Yuyang Du authored
Despite that there is a lockdep_init_task() which does nothing, lockdep initiates tasks by assigning lockdep fields and does so inconsistently. Fix this by using lockdep_init_task(). Signed-off-by:
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Yuyang Du authored
The lock_chain struct definition has outdated comment, update it and add struct member description. Signed-off-by:
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Yuyang Du authored
Since chains are separated by IRQ context, so when printing a chain the depth should be consistent with it. Signed-off-by:
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Yuyang Du authored
Since #defined(CONFIG_PROVE_LOCKING) is used in the scope of #ifdef CONFIG_PROVE_LOCKING, it can be removed. Signed-off-by:
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Yuyang Du authored
The lock usage bit characters are defined and determined with tricks. Add some explanation to make it a bit clearer, then adjust the logic to check the usage, which optimizes the code a bit. No functional change. Signed-off-by:
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Yuyang Du authored
More words are added to lockdep design document regarding key concepts, which should help people without lockdep experience read and understand lockdep reports. Signed-off-by:
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Yuyang Du authored
Since none of the print_*() function's return value is necessary, change their return type to void. No functional change. In cases where an invariable return value is used, this change slightly improves readability, i.e.: print_x(); return 0; is definitely better than: return print_x(); /* where print_x() always returns 0 */ Signed-off-by:
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Ingo Molnar authored
Signed-off-by:
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- 02 Jun, 2019 14 commits
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Linus Torvalds authored
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull x86 fixes from Ingo Molnar: "Two fixes: a quirk for KVM guests running on certain AMD CPUs, and a KASAN related build fix" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/CPU/AMD: Don't force the CPB cap when running under a hypervisor x86/boot: Provide KASAN compatible aliases for string routines
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull perf fixes from Ingo Molnar: "On the kernel side there's a bunch of ring-buffer ordering fixes for a reproducible bug, plus a PEBS constraints regression fix. Plus tooling fixes" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tools headers UAPI: Sync kvm.h headers with the kernel sources perf record: Fix s390 missing module symbol and warning for non-root users perf machine: Read also the end of the kernel perf test vmlinux-kallsyms: Ignore aliases to _etext when searching on kallsyms perf session: Add missing swap ops for namespace events perf namespace: Protect reading thread's namespace tools headers UAPI: Sync drm/drm.h with the kernel tools headers UAPI: Sync drm/i915_drm.h with the kernel tools headers UAPI: Sync linux/fs.h with the kernel tools headers UAPI: Sync linux/sched.h with the kernel tools arch x86: Sync asm/cpufeatures.h with the with the kernel tools include UAPI: Update copy of files related to new fspick, fsmount, fsconfig, fsopen, move_mount and open_tree syscalls perf arm64: Fix mksyscalltbl when system kernel headers are ahead of the kernel perf data: Fix 'strncat may truncate' build failure with recent gcc perf/ring-buffer: Use regular variables for nesting perf/ring-buffer: Always use {READ,WRITE}_ONCE() for rb->user_page data perf/ring_buffer: Add ordering to rb->nest increment perf/ring_buffer: Fix exposing a temporarily decreased data_head perf/x86/intel/ds: Fix EVENT vs. UEVENT PEBS constraints
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull EFI fixes from Ingo Molnar: "Two EFI fixes: a quirk for weird systabs, plus add more robust error handling in the old 1:1 mapping code" * 'efi-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: efi: Allow the number of EFI configuration tables entries to be zero efi/x86/Add missing error handling to old_memmap 1:1 mapping code
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull stacktrace fix from Ingo Molnar: "Fix a stack_trace_save_tsk_reliable() regression" * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: stacktrace: Unbreak stack_trace_save_tsk_reliable()
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-coreLinus Torvalds authored
Pull SPDX fixes from Greg KH: "Here are just two small patches, that fix up some found SPDX identifier issues. The first patch fixes an error in a previous SPDX fixup patch, that causes build errors when doing 'make clean' on the tree (the fact that almost no one noticed it reflects the fact that kernel developers don't like doing that option very often...) The second patch fixes up a number of places in the tree where people mistyped the string "SPDX-License-Identifier". Given that people can not even type their own name all the time without mistakes, this was bound to happen, and odds are, we will have to add some type of check for this to checkpatch.pl to catch this happening in the future. Both of these have passed testing by 0-day" * tag 'spdx-5.2-rc3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: treewide: fix typos of SPDX-License-Identifier crypto: ux500 - fix license comment syntax error
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git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linuxLinus Torvalds authored
Pull powerpc fixes from Michael Ellerman: "A minor fix to our IMC PMU code to print a less confusing error message when the driver can't initialise properly. A fix for a bug where a user requesting an unsupported branch sampling filter can corrupt PMU state, preventing the PMU from counting properly. And finally a fix for a bug in our support for kexec_file_load(), which prevented loading a kernel and initramfs. Most versions of kexec don't yet use kexec_file_load(). Thanks to: Anju T Sudhakar, Dave Young, Madhavan Srinivasan, Ravi Bangoria, Thiago Jung Bauermann" * tag 'powerpc-5.2-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc/kexec: Fix loading of kernel + initramfs with kexec_file_load() powerpc/perf: Fix MMCRA corruption by bhrb_filter powerpc/powernv: Return for invalid IMC domain
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git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds authored
Pull KVM fixes from Paolo Bonzini: "Fixes for PPC and s390" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: PPC: Book3S HV: Restore SPRG3 in kvmhv_p9_guest_entry() KVM: PPC: Book3S HV: Fix lockdep warning when entering guest on POWER9 KVM: PPC: Book3S HV: XIVE: Fix page offset when clearing ESB pages KVM: PPC: Book3S HV: XIVE: Take the srcu read lock when accessing memslots KVM: PPC: Book3S HV: XIVE: Do not clear IRQ data of passthrough interrupts KVM: PPC: Book3S HV: XIVE: Introduce a new mutex for the XIVE device KVM: PPC: Book3S HV: XIVE: Fix the enforced limit on the vCPU identifier KVM: PPC: Book3S HV: XIVE: Do not test the EQ flag validity when resetting KVM: PPC: Book3S HV: XIVE: Clear file mapping when device is released KVM: PPC: Book3S HV: Don't take kvm->lock around kvm_for_each_vcpu KVM: PPC: Book3S: Use new mutex to synchronize access to rtas token list KVM: PPC: Book3S HV: Use new mutex to synchronize MMU setup KVM: PPC: Book3S HV: Avoid touching arch.mmu_ready in XIVE release functions KVM: s390: Do not report unusabled IDs via KVM_CAP_MAX_VCPU_ID kvm: fix compile on s390 part 2
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git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linuxLinus Torvalds authored
Pull i2c fixes from Wolfram Sang: "A memleak fix for the core, two driver bugfixes, as well as fixing missing file patterns to MAINTAINERS" * 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: MAINTAINERS: add I2C DT bindings to ARM platforms MAINTAINERS: add DT bindings to i2c drivers i2c: synquacer: fix synquacer_i2c_doxfer() return value i2c: mlxcpld: Fix wrong initialization order in probe i2c: dev: fix potential memory leak in i2cdev_ioctl_rdwr
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git://git.kernel.org/pub/scm/linux/kernel/git/evalenti/linux-soc-thermalLinus Torvalds authored
Pull thermal SoC fix from Eduardo Valentin: "A single revert, detected to cause issues on the tsens driver" * 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/evalenti/linux-soc-thermal: Revert "drivers: thermal: tsens: Add new operation to check if a sensor is enabled"
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Linus Torvalds authored
Merge tag 'led-fixes-for-5.2-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds Pull LED fix from Jacek Anaszewski: "Fix for a recent change in LED core, that didn't take into account the possibility of calling led_blink_setup() from atomic context" * tag 'led-fixes-for-5.2-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds: leds: avoid flush_work in atomic context
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git://git.kernel.dk/linux-blockLinus Torvalds authored
Pull block fixes from Jens Axboe: - A set of patches fixing code comments / kerneldoc (Bart) - Don't allow loop file change for exclusive open (Jan) - Fix revalidate of hidden genhd (Jan) - Init queue failure memory free fix (Jes) - Improve rq limits failure print (John) - Fixup for queue removal/addition (Ming) - Missed error progagation for io_uring buffer registration (Pavel) * tag 'for-linus-20190601' of git://git.kernel.dk/linux-block: block: print offending values when cloned rq limits are exceeded blk-mq: Document the blk_mq_hw_queue_to_node() arguments blk-mq: Fix spelling in a source code comment block: Fix bsg_setup_queue() kernel-doc header block: Fix rq_qos_wait() kernel-doc header block: Fix blk_mq_*_map_queues() kernel-doc headers block: Fix throtl_pending_timer_fn() kernel-doc header block: Convert blk_invalidate_devt() header into a non-kernel-doc header block/partitions/ldm: Convert a kernel-doc header into a non-kernel-doc header blk-mq: Fix memory leak in error handling block: don't protect generic_make_request_checks with blk_queue_enter block: move blk_exit_queue into __blk_release_queue block: Don't revalidate bdev of hidden gendisk loop: Don't change loop device under exclusive opener io_uring: Fix __io_uring_register() false success
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git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsiLinus Torvalds authored
Pull SCSI fixes from James Bottomley: "Six minor fixes to device drivers and one to the multipath alua handler. The most extensive fix is the zfcp port remove prevention one, but it's impact is only s390" * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: scsi: libsas: delete sas port if expander discover failed scsi: libsas: only clear phy->in_shutdown after shutdown event done scsi: scsi_dh_alua: Fix possible null-ptr-deref scsi: smartpqi: properly set both the DMA mask and the coherent DMA mask scsi: zfcp: fix to prevent port_remove with pure auto scan LUNs (only sdevs) scsi: zfcp: fix missing zfcp_port reference put on -EBUSY from port_remove scsi: libcxgbi: add a check for NULL pointer in cxgbi_check_route()
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Linus Torvalds authored
Merge misc fixes from Andrew Morton: "Various fixes and followups" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: mm, compaction: make sure we isolate a valid PFN include/linux/generic-radix-tree.h: fix kerneldoc comment kernel/signal.c: trace_signal_deliver when signal_group_exit drivers/iommu/intel-iommu.c: fix variable 'iommu' set but not used spdxcheck.py: fix directory structures kasan: initialize tag to 0xff in __kasan_kmalloc z3fold: fix sheduling while atomic scripts/gdb: fix invocation when CONFIG_COMMON_CLK is not set mm/gup: continue VM_FAULT_RETRY processing even for pre-faults ocfs2: fix error path kobject memory leak memcg: make it work on sparse non-0-node systems mm, memcg: consider subtrees in memory.events prctl_set_mm: downgrade mmap_sem to read lock prctl_set_mm: refactor checks from validate_prctl_map kernel/fork.c: make max_threads symbol static arch/arm/boot/compressed/decompress.c: fix build error due to lz4 changes arch/parisc/configs/c8000_defconfig: remove obsoleted CONFIG_DEBUG_SLAB_LEAK mm/vmalloc.c: fix typo in comment lib/sort.c: fix kernel-doc notation warnings mm: fix Documentation/vm/hmm.rst Sphinx warnings
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