user/sven/linux.git/kernel/hung_task.c, branch v5.15.91

Merge branch 'akpm' (patches from Andrew)

2021-07-02T19:08:10Z

Merge more updates from Andrew Morton: "190 patches. Subsystems affected by this patch series: mm (hugetlb, userfaultfd, vmscan, kconfig, proc, z3fold, zbud, ras, mempolicy, memblock, migration, thp, nommu, kconfig, madvise, memory-hotplug, zswap, zsmalloc, zram, cleanups, kfence, and hmm), procfs, sysctl, misc, core-kernel, lib, lz4, checkpatch, init, kprobes, nilfs2, hfs, signals, exec, kcov, selftests, compress/decompress, and ipc" * emailed patches from Andrew Morton : (190 commits) ipc/util.c: use binary search for max_idx ipc/sem.c: use READ_ONCE()/WRITE_ONCE() for use_global_lock ipc: use kmalloc for msg_queue and shmid_kernel ipc sem: use kvmalloc for sem_undo allocation lib/decompressors: remove set but not used variabled 'level' selftests/vm/pkeys: exercise x86 XSAVE init state selftests/vm/pkeys: refill shadow register after implicit kernel write selftests/vm/pkeys: handle negative sys_pkey_alloc() return code selftests/vm/pkeys: fix alloc_random_pkey() to make it really, really random kcov: add __no_sanitize_coverage to fix noinstr for all architectures exec: remove checks in __register_bimfmt() x86: signal: don't do sas_ss_reset() until we are certain that sigframe won't be abandoned hfsplus: report create_date to kstat.btime hfsplus: remove unnecessary oom message nilfs2: remove redundant continue statement in a while-loop kprobes: remove duplicated strong free_insn_page in x86 and s390 init: print out unknown kernel parameters checkpatch: do not complain about positive return values starting with EPOLL checkpatch: improve the indented label test checkpatch: scripts/spdxcheck.py now requires python3 ...

kernel.h: split out panic and oops helpers

2021-07-01T18:06:04Z

kernel.h is being used as a dump for all kinds of stuff for a long time. Here is the attempt to start cleaning it up by splitting out panic and oops helpers. There are several purposes of doing this: - dropping dependency in bug.h - dropping a loop by moving out panic_notifier.h - unload kernel.h from something which has its own domain At the same time convert users tree-wide to use new headers, although for the time being include new header back to kernel.h to avoid twisted indirected includes for existing users. [akpm@linux-foundation.org: thread_info.h needs limits.h] [andriy.shevchenko@linux.intel.com: ia64 fix] Link: https://lkml.kernel.org/r/20210520130557.55277-1-andriy.shevchenko@linux.intel.com Link: https://lkml.kernel.org/r/20210511074137.33666-1-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Reviewed-by: Bjorn Andersson Co-developed-by: Andrew Morton Acked-by: Mike Rapoport Acked-by: Corey Minyard Acked-by: Christian Brauner Acked-by: Arnd Bergmann Acked-by: Kees Cook Acked-by: Wei Liu Acked-by: Rasmus Villemoes Signed-off-by: Andrew Morton Acked-by: Sebastian Reichel Acked-by: Luis Chamberlain Acked-by: Stephen Boyd Acked-by: Thomas Bogendoerfer Acked-by: Helge Deller # parisc Signed-off-by: Linus Torvalds

sched: Change task_struct::state

2021-06-18T09:43:09Z

Change the type and name of task_struct::state. Drop the volatile and shrink it to an 'unsigned int'. Rename it in order to find all uses such that we can use READ_ONCE/WRITE_ONCE as appropriate. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Daniel Bristot de Oliveira Acked-by: Will Deacon Acked-by: Daniel Thompson Link: https://lore.kernel.org/r/20210611082838.550736351@infradead.org

kernel/hung_task.c: make type annotations consistent

2020-11-02T20:14:19Z

Commit 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler") removed various __user annotations from function signatures as part of its refactoring. It also removed the __user annotation for proc_dohung_task_timeout_secs() at its declaration in sched/sysctl.h, but not at its definition in kernel/hung_task.c. Hence, sparse complains: kernel/hung_task.c:271:5: error: symbol 'proc_dohung_task_timeout_secs' redeclared with different type (incompatible argument 3 (different address spaces)) Adjust the annotation at the definition fitting to that refactoring to make sparse happy again, which also resolves this warning from sparse: kernel/hung_task.c:277:52: warning: incorrect type in argument 3 (different address spaces) kernel/hung_task.c:277:52: expected void * kernel/hung_task.c:277:52: got void [noderef] __user *buffer No functional change. No change in object code. Signed-off-by: Lukas Bulwahn Signed-off-by: Andrew Morton Cc: Christoph Hellwig Cc: Tetsuo Handa Cc: Al Viro Cc: Andrey Ignatov Link: https://lkml.kernel.org/r/20201028130541.20320-1-lukas.bulwahn@gmail.com Signed-off-by: Linus Torvalds

kernel/hung_task.c: introduce sysctl to print all traces when a hung task is detected

2020-06-08T18:05:56Z

Commit 401c636a0eeb ("kernel/hung_task.c: show all hung tasks before panic") introduced a change in that we started to show all CPUs backtraces when a hung task is detected _and_ the sysctl/kernel parameter "hung_task_panic" is set. The idea is good, because usually when observing deadlocks (that may lead to hung tasks), the culprit is another task holding a lock and not necessarily the task detected as hung. The problem with this approach is that dumping backtraces is a slightly expensive task, specially printing that on console (and specially in many CPU machines, as servers commonly found nowadays). So, users that plan to collect a kdump to investigate the hung tasks and narrow down the deadlock definitely don't need the CPUs backtrace on dmesg/console, which will delay the panic and pollute the log (crash tool would easily grab all CPUs traces with 'bt -a' command). Also, there's the reciprocal scenario: some users may be interested in seeing the CPUs backtraces but not have the system panic when a hung task is detected. The current approach hence is almost as embedding a policy in the kernel, by forcing the CPUs backtraces' dump (only) on hung_task_panic. This patch decouples the panic event on hung task from the CPUs backtraces dump, by creating (and documenting) a new sysctl called "hung_task_all_cpu_backtrace", analog to the approach taken on soft/hard lockups, that have both a panic and an "all_cpu_backtrace" sysctl to allow individual control. The new mechanism for dumping the CPUs backtraces on hung task detection respects "hung_task_warnings" by not dumping the traces in case there's no warnings left. Signed-off-by: Guilherme G. Piccoli Signed-off-by: Andrew Morton Reviewed-by: Kees Cook Cc: Tetsuo Handa Link: http://lkml.kernel.org/r/20200327223646.20779-1-gpiccoli@canonical.com Signed-off-by: Linus Torvalds

kernel/hung_task convert hung_task_panic boot parameter to sysctl

2020-06-08T18:05:56Z

We can now handle sysctl parameters on kernel command line and have infrastructure to convert legacy command line options that duplicate sysctl to become a sysctl alias. This patch converts the hung_task_panic parameter. Note that the sysctl handler is more strict and allows only 0 and 1, while the legacy parameter allowed any non-zero value. But there is little reason anyone would not be using 1. Signed-off-by: Vlastimil Babka Signed-off-by: Andrew Morton Reviewed-by: Kees Cook Acked-by: Michal Hocko Cc: Alexey Dobriyan Cc: Christian Brauner Cc: David Rientjes Cc: "Eric W . Biederman" Cc: Greg Kroah-Hartman Cc: "Guilherme G . Piccoli" Cc: Iurii Zaikin Cc: Ivan Teterevkov Cc: Luis Chamberlain Cc: Masami Hiramatsu Cc: Matthew Wilcox Cc: Michal Hocko Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20200427180433.7029-4-vbabka@suse.cz Signed-off-by: Linus Torvalds

treewide: Add SPDX license identifier for missed files

2019-05-21T08:50:45Z

Add SPDX license identifiers to all files which: - Have no license information of any form - Have EXPORT_.*_SYMBOL_GPL inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

kernel/hung_task.c: Use continuously blocked time when reporting.

2019-03-08T02:31:59Z

Since commit a2e514453861 ("kernel/hung_task.c: allow to set checking interval separately from timeout") added hung_task_check_interval_secs, setting a value different from hung_task_timeout_secs echo 0 > /proc/sys/kernel/hung_task_panic echo 120 > /proc/sys/kernel/hung_task_timeout_secs echo 5 > /proc/sys/kernel/hung_task_check_interval_secs causes confusing output as if the task was blocked for hung_task_timeout_secs seconds from the previous report. [ 399.395930] INFO: task kswapd0:75 blocked for more than 120 seconds. [ 405.027637] INFO: task kswapd0:75 blocked for more than 120 seconds. [ 410.659725] INFO: task kswapd0:75 blocked for more than 120 seconds. [ 416.292860] INFO: task kswapd0:75 blocked for more than 120 seconds. [ 421.932305] INFO: task kswapd0:75 blocked for more than 120 seconds. Although we could update t->last_switch_time after sched_show_task(t) if we want to report only every 120 seconds, reporting every 5 seconds might not be very bad for monitoring after a problematic situation has started. Thus, let's use continuously blocked time instead of updating previously reported time. [ 677.985011] INFO: task kswapd0:80 blocked for more than 122 seconds. [ 693.856126] INFO: task kswapd0:80 blocked for more than 138 seconds. [ 709.728075] INFO: task kswapd0:80 blocked for more than 154 seconds. [ 725.600018] INFO: task kswapd0:80 blocked for more than 170 seconds. [ 741.473133] INFO: task kswapd0:80 blocked for more than 186 seconds. Link: http://lkml.kernel.org/r/1551175083-10669-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp Signed-off-by: Tetsuo Handa Acked-by: Dmitry Vyukov Cc: "Paul E. McKenney" Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel/hung_task.c - fix sparse warnings

2019-03-08T02:31:59Z

sparse complains: CHECK kernel/hung_task.c kernel/hung_task.c:28:19: warning: symbol 'sysctl_hung_task_check_count' was not declared. Should it be static? kernel/hung_task.c:42:29: warning: symbol 'sysctl_hung_task_timeout_secs' was not declared. Should it be static? kernel/hung_task.c:47:29: warning: symbol 'sysctl_hung_task_check_interval_secs' was not declared. Should it be static? kernel/hung_task.c:49:19: warning: symbol 'sysctl_hung_task_warnings' was not declared. Should it be static? kernel/hung_task.c:61:28: warning: symbol 'sysctl_hung_task_panic' was not declared. Should it be static? kernel/hung_task.c:219:5: warning: symbol 'proc_dohung_task_timeout_secs' was not declared. Should it be static? Add the appropriate header file to provide declarations. Link: http://lkml.kernel.org/r/467.1548649525@turing-police.cc.vt.edu Signed-off-by: Valdis Kletnieks Cc: "Paul E. McKenney" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel/hung_task.c: break RCU locks based on jiffies

2019-01-04T21:13:45Z

check_hung_uninterruptible_tasks() is currently calling rcu_lock_break() for every 1024 threads. But check_hung_task() is very slow if printk() was called, and is very fast otherwise. If many threads within some 1024 threads called printk(), the RCU grace period might be extended enough to trigger RCU stall warnings. Therefore, calling rcu_lock_break() for every some fixed jiffies will be safer. Link: http://lkml.kernel.org/r/1544800658-11423-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp Signed-off-by: Tetsuo Handa Acked-by: Paul E. McKenney Cc: Petr Mladek Cc: Sergey Senozhatsky Cc: Dmitry Vyukov Cc: "Rafael J. Wysocki" Cc: Vitaly Kuznetsov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds