user/sven/linux.git/kernel/locking, branch v6.6.14

lockdep: Fix block chain corruption

2023-12-03T06:33:06Z

[ Upstream commit bca4104b00fec60be330cd32818dd5c70db3d469 ] Kent reported an occasional KASAN splat in lockdep. Mark then noted: > I suspect the dodgy access is to chain_block_buckets[-1], which hits the last 4 > bytes of the redzone and gets (incorrectly/misleadingly) attributed to > nr_large_chain_blocks. That would mean @size == 0, at which point size_to_bucket() returns -1 and the above happens. alloc_chain_hlocks() has 'size - req', for the first with the precondition 'size >= rq', which allows the 0. This code is trying to split a block, del_chain_block() takes what we need, and add_chain_block() puts back the remainder, except in the above case the remainder is 0 sized and things go sideways. Fixes: 810507fe6fd5 ("locking/lockdep: Reuse freed chain_hlocks entries") Reported-by: Kent Overstreet Signed-off-by: Peter Zijlstra (Intel) Tested-by: Kent Overstreet Link: https://lkml.kernel.org/r/20231121114126.GH8262@noisy.programming.kicks-ass.net Signed-off-by: Sasha Levin

locking/ww_mutex/test: Fix potential workqueue corruption

2023-11-28T17:19:35Z

[ Upstream commit bccdd808902f8c677317cec47c306e42b93b849e ] In some cases running with the test-ww_mutex code, I was seeing odd behavior where sometimes it seemed flush_workqueue was returning before all the work threads were finished. Often this would cause strange crashes as the mutexes would be freed while they were being used. Looking at the code, there is a lifetime problem as the controlling thread that spawns the work allocates the "struct stress" structures that are passed to the workqueue threads. Then when the workqueue threads are finished, they free the stress struct that was passed to them. Unfortunately the workqueue work_struct node is in the stress struct. Which means the work_struct is freed before the work thread returns and while flush_workqueue is waiting. It seems like a better idea to have the controlling thread both allocate and free the stress structures, so that we can be sure we don't corrupt the workqueue by freeing the structure prematurely. So this patch reworks the test to do so, and with this change I no longer see the early flush_workqueue returns. Signed-off-by: John Stultz Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20230922043616.19282-3-jstultz@google.com Signed-off-by: Sasha Levin

Merge tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-08-29T21:53:51Z

Pull non-MM updates from Andrew Morton: - An extensive rework of kexec and crash Kconfig from Eric DeVolder ("refactor Kconfig to consolidate KEXEC and CRASH options") - kernel.h slimming work from Andy Shevchenko ("kernel.h: Split out a couple of macros to args.h") - gdb feature work from Kuan-Ying Lee ("Add GDB memory helper commands") - vsprintf inclusion rationalization from Andy Shevchenko ("lib/vsprintf: Rework header inclusions") - Switch the handling of kdump from a udev scheme to in-kernel handling, by Eric DeVolder ("crash: Kernel handling of CPU and memory hot un/plug") - Many singleton patches to various parts of the tree * tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (81 commits) document while_each_thread(), change first_tid() to use for_each_thread() drivers/char/mem.c: shrink character device's devlist[] array x86/crash: optimize CPU changes crash: change crash_prepare_elf64_headers() to for_each_possible_cpu() crash: hotplug support for kexec_load() x86/crash: add x86 crash hotplug support crash: memory and CPU hotplug sysfs attributes kexec: exclude elfcorehdr from the segment digest crash: add generic infrastructure for crash hotplug support crash: move a few code bits to setup support of crash hotplug kstrtox: consistently use _tolower() kill do_each_thread() nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse scripts/bloat-o-meter: count weak symbol sizes treewide: drop CONFIG_EMBEDDED lockdep: fix static memory detection even more lib/vsprintf: declare no_hash_pointers in sprintf.h lib/vsprintf: split out sprintf() and friends kernel/fork: stop playing lockless games for exe_file replacement adfs: delete unused "union adfs_dirtail" definition ...

Merge tag 'x86-cleanups-2023-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2023-08-29T00:05:58Z

Pull misc x86 cleanups from Ingo Molnar: "The following commit deserves special mention: 22dc02f81cddd Revert "sched/fair: Move unused stub functions to header" This is in x86/cleanups, because the revert is a re-application of a number of cleanups that got removed inadvertedly" [ This also effectively undoes the amd_check_microcode() microcode declaration change I had done in my microcode loader merge in commit 42a7f6e3ffe0 ("Merge tag 'x86_microcode_for_v6.6_rc1' [...]"). I picked the declaration change by Arnd from this branch instead, which put it in instead of like I had done in my merge resolution - Linus ] * tag 'x86-cleanups-2023-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/platform/uv: Refactor code using deprecated strncpy() interface to use strscpy() x86/hpet: Refactor code using deprecated strncpy() interface to use strscpy() x86/platform/uv: Refactor code using deprecated strcpy()/strncpy() interfaces to use strscpy() x86/qspinlock-paravirt: Fix missing-prototype warning x86/paravirt: Silence unused native_pv_lock_init() function warning x86/alternative: Add a __alt_reloc_selftest() prototype x86/purgatory: Include header for warn() declaration x86/asm: Avoid unneeded __div64_32 function definition Revert "sched/fair: Move unused stub functions to header" x86/apic: Hide unused safe_smp_processor_id() on 32-bit UP x86/cpu: Fix amd_check_microcode() declaration

Merge tag 'rcu.2023.08.21a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

2023-08-28T20:19:28Z

Pull RCU updates from Paul McKenney: - Documentation updates - Miscellaneous fixes, perhaps most notably simplifying SRCU_NOTIFIER_INIT() as suggested - RCU Tasks updates, most notably treating Tasks RCU callbacks as lazy while still treating synchronous grace periods as urgent. Also fixes one bug that restores the ability to apply debug-objects to RCU Tasks and another that fixes a race condition that could result in false-positive failures of the boot-time self-test code - RCU-scalability performance-test updates, most notably adding the ability to measure the RCU-Tasks's grace-period kthread's CPU consumption. This proved quite useful for the RCU Tasks work - Reference-acquisition/release performance-test updates, including a fix for an uninitialized wait_queue_head_t - Miscellaneous torture-test updates - Torture-test scripting updates, including removal of the non-longer-functional formal-verification scripts, test builds of individual RCU Tasks flavors, better diagnostics for loss of connectivity for distributed rcutorture tests, disabling of reboot loops in qemu/KVM-based rcutorture testing, and passing of init parameters to rcutorture's init program * tag 'rcu.2023.08.21a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (64 commits) rcu: Use WRITE_ONCE() for assignments to ->next for rculist_nulls rcu: Make the rcu_nocb_poll boot parameter usable via boot config rcu: Mark __rcu_irq_enter_check_tick() ->rcu_urgent_qs load srcu,notifier: Remove #ifdefs in favor of SRCU Tiny srcu_usage rcutorture: Stop right-shifting torture_random() return values torture: Stop right-shifting torture_random() return values torture: Move stutter_wait() timeouts to hrtimers torture: Move torture_shuffle() timeouts to hrtimers torture: Move torture_onoff() timeouts to hrtimers torture: Make torture_hrtimeout_*() use TASK_IDLE torture: Add lock_torture writer_fifo module parameter torture: Add a kthread-creation callback to _torture_create_kthread() rcu-tasks: Fix boot-time RCU tasks debug-only deadlock rcu-tasks: Permit use of debug-objects with RCU Tasks flavors checkpatch: Complain about unexpected uses of RCU Tasks Trace torture: Cause mkinitrd.sh to indicate failure on compile errors torture: Make init program dump command-line arguments torture: Switch qemu from -nographic to -display none torture: Add init-program support for loongarch torture: Avoid torture-test reboot loops ...

lockdep: fix static memory detection even more

2023-08-21T20:46:24Z

On the parisc architecture, lockdep reports for all static objects which are in the __initdata section (e.g. "setup_done" in devtmpfs, "kthreadd_done" in init/main.c) this warning: INFO: trying to register non-static key. The warning itself is wrong, because those objects are in the __initdata section, but the section itself is on parisc outside of range from _stext to _end, which is why the static_obj() functions returns a wrong answer. While fixing this issue, I noticed that the whole existing check can be simplified a lot. Instead of checking against the _stext and _end symbols (which include code areas too) just check for the .data and .bss segments (since we check a data object). This can be done with the existing is_kernel_core_data() macro. In addition objects in the __initdata section can be checked with init_section_contains(), and is_kernel_rodata() allows keys to be in the _ro_after_init section. This partly reverts and simplifies commit bac59d18c701 ("x86/setup: Fix static memory detection"). Link: https://lkml.kernel.org/r/ZNqrLRaOi/3wPAdp@p100 Fixes: bac59d18c701 ("x86/setup: Fix static memory detection") Signed-off-by: Helge Deller Cc: Borislav Petkov Cc: Greg Kroah-Hartman Cc: Guenter Roeck Cc: Peter Zijlstra Cc: "Rafael J. Wysocki" Signed-off-by: Andrew Morton

torture: Add lock_torture writer_fifo module parameter

2023-08-14T22:01:07Z

This commit adds a module parameter that causes the locktorture writer to run at real-time priority. To use it: insmod /lib/modules/torture.ko random_shuffle=1 insmod /lib/modules/locktorture.ko torture_type=mutex_lock rt_boost=1 rt_boost_factor=50 nested_locks=3 writer_fifo=1 ^^^^^^^^^^^^^ A predecessor to this patch has been helpful to uncover issues with the proxy-execution series. [ paulmck: Remove locktorture-specific code from kernel/torture.c. ] Cc: "Paul E. McKenney" Cc: Josh Triplett Cc: Joel Fernandes Cc: Juri Lelli Cc: Valentin Schneider Cc: kernel-team@android.com Signed-off-by: Dietmar Eggemann [jstultz: Include header change to build, reword commit message] Signed-off-by: John Stultz Acked-by: Davidlohr Bueso Signed-off-by: Paul E. McKenney

x86/qspinlock-paravirt: Fix missing-prototype warning

2023-08-03T15:15:05Z

__pv_queued_spin_unlock_slowpath() is defined in a header file as a global function, and designed to be called from inline asm, but there is no prototype visible in the definition: kernel/locking/qspinlock_paravirt.h:493:1: error: no previous \ prototype for '__pv_queued_spin_unlock_slowpath' [-Werror=missing-prototypes] Add this to the x86 header that contains the inline asm calling it, and ensure this gets included before the definition, rather than after it. Signed-off-by: Arnd Bergmann Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20230803082619.1369127-8-arnd@kernel.org

locking/rtmutex: Fix task->pi_waiters integrity

2023-07-17T11:59:10Z

Henry reported that rt_mutex_adjust_prio_check() has an ordering problem and puts the lie to the comment in [7]. Sharing the sort key between lock->waiters and owner->pi_waiters *does* create problems, since unlike what the comment claims, holding [L] is insufficient. Notably, consider: A / \ M1 M2 | | B C That is, task A owns both M1 and M2, B and C block on them. In this case a concurrent chain walk (B & C) will modify their resp. sort keys in [7] while holding M1->wait_lock and M2->wait_lock. So holding [L] is meaningless, they're different Ls. This then gives rise to a race condition between [7] and [11], where the requeue of pi_waiters will observe an inconsistent tree order. B C (holds M1->wait_lock, (holds M2->wait_lock, holds B->pi_lock) holds A->pi_lock) [7] waiter_update_prio(); ... [8] raw_spin_unlock(B->pi_lock); ... [10] raw_spin_lock(A->pi_lock); [11] rt_mutex_enqueue_pi(); // observes inconsistent A->pi_waiters // tree order Fixing this means either extending the range of the owner lock from [10-13] to [6-13], with the immediate problem that this means [6-8] hold both blocked and owner locks, or duplicating the sort key. Since the locking in chain walk is horrible enough without having to consider pi_lock nesting rules, duplicate the sort key instead. By giving each tree their own sort key, the above race becomes harmless, if C sees B at the old location, then B will correct things (if they need correcting) when it walks up the chain and reaches A. Fixes: fb00aca47440 ("rtmutex: Turn the plist into an rb-tree") Reported-by: Henry Wu Signed-off-by: Peter Zijlstra (Intel) Acked-by: Thomas Gleixner Tested-by: Henry Wu Link: https://lkml.kernel.org/r/20230707161052.GF2883469%40hirez.programming.kicks-ass.net

Merge tag 'mm-nonmm-stable-2023-06-24-19-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-06-28T17:59:38Z

Pull non-mm updates from Andrew Morton: - Arnd Bergmann has fixed a bunch of -Wmissing-prototypes in top-level directories - Douglas Anderson has added a new "buddy" mode to the hardlockup detector. It permits the detector to work on architectures which cannot provide the required interrupts, by having CPUs periodically perform checks on other CPUs - Zhen Lei has enhanced kexec's ability to support two crash regions - Petr Mladek has done a lot of cleanup on the hard lockup detector's Kconfig entries - And the usual bunch of singleton patches in various places * tag 'mm-nonmm-stable-2023-06-24-19-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (72 commits) kernel/time/posix-stubs.c: remove duplicated include ocfs2: remove redundant assignment to variable bit_off watchdog/hardlockup: fix typo in config HARDLOCKUP_DETECTOR_PREFER_BUDDY powerpc: move arch_trigger_cpumask_backtrace from nmi.h to irq.h devres: show which resource was invalid in __devm_ioremap_resource() watchdog/hardlockup: define HARDLOCKUP_DETECTOR_ARCH watchdog/sparc64: define HARDLOCKUP_DETECTOR_SPARC64 watchdog/hardlockup: make HAVE_NMI_WATCHDOG sparc64-specific watchdog/hardlockup: declare arch_touch_nmi_watchdog() only in linux/nmi.h watchdog/hardlockup: make the config checks more straightforward watchdog/hardlockup: sort hardlockup detector related config values a logical way watchdog/hardlockup: move SMP barriers from common code to buddy code watchdog/buddy: simplify the dependency for HARDLOCKUP_DETECTOR_PREFER_BUDDY watchdog/buddy: don't copy the cpumask in watchdog_next_cpu() watchdog/buddy: cleanup how watchdog_buddy_check_hardlockup() is called watchdog/hardlockup: remove softlockup comment in touch_nmi_watchdog() watchdog/hardlockup: in watchdog_hardlockup_check() use cpumask_copy() watchdog/hardlockup: don't use raw_cpu_ptr() in watchdog_hardlockup_kick() watchdog/hardlockup: HAVE_NMI_WATCHDOG must implement watchdog_hardlockup_probe() watchdog/hardlockup: keep kernel.nmi_watchdog sysctl as 0444 if probe fails ...