Repository files (latest commit first)

Filename	Latest commit message	Latest commit date
Petr Mladek c24de62408 tracing: Initialize iter->seq after zeroing in tracing_read_pipe() ... [ Upstream commit d303de1fcf344ff7c15ed64c3f48a991c9958775 ] A customer reported the following softlockup: [899688.160002] NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [test.sh:16464] [899688.160002] CPU: 0 PID: 16464 Comm: test.sh Not tainted 4.12.14-6.23-azure #1 SLE12-SP4 [899688.160002] RIP: 0010:up_write+0x1a/0x30 [899688.160002] Kernel panic - not syncing: softlockup: hung tasks [899688.160002] RIP: 0010:up_write+0x1a/0x30 [899688.160002] RSP: 0018:ffffa86784d4fde8 EFLAGS: 00000257 ORIG_RAX: ffffffffffffff12 [899688.160002] RAX: ffffffff970fea00 RBX: 0000000000000001 RCX: 0000000000000000 [899688.160002] RDX: ffffffff00000001 RSI: 0000000000000080 RDI: ffffffff970fea00 [899688.160002] RBP: ffffffffffffffff R08: ffffffffffffffff R09: 0000000000000000 [899688.160002] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8b59014720d8 [899688.160002] R13: ffff8b59014720c0 R14: ffff8b5901471090 R15: ffff8b5901470000 [899688.160002] tracing_read_pipe+0x336/0x3c0 [899688.160002] __vfs_read+0x26/0x140 [899688.160002] vfs_read+0x87/0x130 [899688.160002] SyS_read+0x42/0x90 [899688.160002] do_syscall_64+0x74/0x160 It caught the process in the middle of trace_access_unlock(). There is no loop. So, it must be looping in the caller tracing_read_pipe() via the "waitagain" label. Crashdump analyze uncovered that iter->seq was completely zeroed at this point, including iter->seq.seq.size. It means that print_trace_line() was never able to print anything and there was no forward progress. The culprit seems to be in the code: /* reset all but tr, trace, and overruns */ memset(&iter->seq, 0, sizeof(struct trace_iterator) - offsetof(struct trace_iterator, seq)); It was added by the commit 53d0aa7730 ("ftrace: add logic to record overruns"). It was v2.6.27-rc1. It was the time when iter->seq looked like: struct trace_seq { unsigned char buffer[PAGE_SIZE]; unsigned int len; }; There was no "size" variable and zeroing was perfectly fine. The solution is to reinitialize the structure after or without zeroing. Link: http://lkml.kernel.org/r/20191011142134.11997-1-pmladek@suse.com Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>		2019-11-06 12:18:13 +01:00
..
bpf	bpf: fix bpf_jit_limit knob for PAGE_SIZE >= 64K	2019-08-25 10:51:50 +02:00
configs	config: android: enable CONFIG_SECCOMP	2016-10-11 15:06:32 -07:00
debug	kdb: use memmove instead of overlapping memcpy	2018-12-08 13:05:05 +01:00
events	perf/core: Fix creating kernel counters for PMUs that override event->cpu	2019-08-25 10:51:35 +02:00
gcov	gcov: support GCC 7.1	2017-09-02 07:07:53 +02:00
irq	genirq: Prevent NULL pointer dereference in resend_irqs()	2019-09-21 07:14:04 +02:00
livepatch	livepatch/module: make TAINT_LIVEPATCH module-specific	2016-08-26 14:42:08 +02:00
locking	locking/lockdep: Add debug_locks check in __lock_downgrade()	2019-10-05 12:30:10 +02:00
power	x86/power: Fix 'nosmt' vs hibernation triple fault during resume	2019-06-11 12:22:48 +02:00
printk	printk: Do not lose last line in kmsg buffer dump	2019-10-05 12:30:31 +02:00
rcu	rcuperf: Fix cleanup path for invalid perf_type strings	2019-05-31 06:48:30 -07:00
sched	sched/core: Fix migration to invalid CPU in __set_cpus_allowed_ptr()	2019-10-17 13:42:13 -07:00
time	timer: Read jiffies once when forwarding base clk	2019-10-17 13:42:06 -07:00
trace	tracing: Initialize iter->seq after zeroing in tracing_read_pipe()	2019-11-06 12:18:13 +01:00
.gitignore
acct.c	kernel/acct.c: fix the acct->needcheck check in check_free_space()	2018-01-10 09:29:51 +01:00
async.c	kernel/async.c: revert "async: simplify lowest_in_progress()"	2018-02-17 13:21:18 +01:00
audit.c	audit: return on memory error to avoid null pointer dereference	2018-05-30 07:50:49 +02:00
audit.h	Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit	2016-07-29 17:54:17 -07:00
audit_fsnotify.c
audit_tree.c
audit_watch.c	audit: fix use-after-free in audit_add_watch	2018-09-26 08:36:37 +02:00
auditfilter.c	audit: fix a memory leak bug	2019-05-31 06:48:20 -07:00
auditsc.c	audit: allow not equal op for audit by executable	2018-08-03 07:55:25 +02:00
backtracetest.c
bounds.c	kbuild: fix kernel/bounds.c 'W=1' warning	2018-11-13 11:16:57 -08:00
capability.c	ptrace: Capture the ptracer's creds not PT_PTRACE_CAP	2017-01-06 10:40:13 +01:00
cgroup.c	cgroup: Fix deadlock in cpu hotplug path	2018-10-13 09:18:56 +02:00
cgroup_freezer.c
cgroup_pids.c	cgroup/pids: remove spurious suspicious RCU usage warning	2017-03-26 13:05:58 +02:00
compat.c
configs.c
context_tracking.c
cpu.c	cpu/speculation: Warn on unsupported mitigations= parameter	2019-07-10 09:55:39 +02:00
cpu_pm.c
cpuset.c	sched/cpuset/pm: Fix cpuset vs. suspend-resume bugs	2017-10-12 11:51:25 +02:00
crash_dump.c
cred.c	access: avoid the RCU grace period for the temporary subjective credentials	2019-08-04 09:33:43 +02:00
delayacct.c
dma.c
elfcore.c	kernel/elfcore.c: include proper prototypes	2019-10-17 13:42:13 -07:00
exec_domain.c
exit.c	kernel/exit.c: release ptraced tasks before zap_pid_ns_processes	2019-02-06 17:33:29 +01:00
extable.c	kernel/extable.c: mark core_kernel_text notrace	2017-07-21 07:42:21 +02:00
fork.c	kernel/sysctl.c: do not override max_threads provided by userspace	2019-10-17 13:42:44 -07:00
freezer.c	freezer, oom: check TIF_MEMDIE on the correct task	2016-07-28 16:07:41 -07:00
futex.c	futex: Ensure that futex address is aligned in handle_futex_death()	2019-03-27 14:13:03 +09:00
futex_compat.c
groups.c	kernel: make groups_sort calling a responsibility group_info allocators	2018-01-10 09:29:52 +01:00
hung_task.c	kernel: hung_task.c: disable on suspend	2019-04-20 09:07:52 +02:00
irq_work.c
jump_label.c	jump_label: Invoke jump_label_test() via early_initcall()	2017-12-14 09:28:24 +01:00
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c	kcov: ensure irq code sees a valid area	2018-08-03 07:55:12 +02:00
kexec.c	kexec: allow architectures to override boot mapping	2016-08-02 19:35:27 -04:00
kexec_core.c	objtool, x86: Add several functions and files to the objtool whitelist	2018-06-05 10:28:57 +02:00
kexec_file.c	kexec: fix double-free when failing to relocate the purgatory	2016-09-01 17:52:01 -07:00
kexec_internal.h
kmod.c
kprobes.c	kprobes: Prohibit probing on BUG() and WARN() address	2019-10-05 12:30:26 +02:00
ksysfs.c	kexec: add a kexec_crash_loaded() function	2016-08-02 19:35:30 -04:00
kthread.c	kthread, tracing: Don't expose half-written comm when creating kthreads	2018-08-03 07:55:12 +02:00
latencytop.c
Makefile	x86/uaccess, kcov: Disable stack protector	2019-06-22 08:17:19 +02:00
membarrier.c	Fix: Disable sys_membarrier when nohz_full is enabled	2017-03-12 06:41:45 +01:00
memremap.c	mm, devm_memremap_pages: kill mapping "System RAM" support	2019-01-13 10:03:51 +01:00
module-internal.h
module.c	kernel/module.c: Only return -EEXIST for modules that have finished loading	2019-08-06 18:29:35 +02:00
module_signing.c
notifier.c
nsproxy.c
padata.c	padata: use smp_mb in padata_reorder to avoid orphaned padata jobs	2019-08-04 09:33:28 +02:00
panic.c	panic: ensure preemption is disabled during panic()	2019-10-17 13:42:25 -07:00
params.c
pid.c	pidns: disable pid allocation if pid_ns_prepare_proc() is failed in alloc_pid()	2018-04-13 19:47:53 +02:00
pid_namespace.c	signal/pid_namespace: Fix reboot_pid_ns to use send_sig not force_sig	2019-08-04 09:33:16 +02:00
profile.c	profile: Convert to hotplug state machine	2016-07-15 10:41:42 +02:00
ptrace.c	ptrace: Fix ->ptracer_cred handling for PTRACE_TRACEME	2019-07-10 09:55:45 +02:00
range.c
reboot.c
relay.c	kernel/relay.c: limit kmalloc size to KMALLOC_MAX_SIZE	2018-05-30 07:50:29 +02:00
resource.c	resource: fix integer overflow at reallocation	2018-04-24 09:34:09 +02:00
seccomp.c	seccomp: Move speculation migitation control to arch code	2018-05-22 16:58:02 +02:00
signal.c	kernel/signal.c: trace_signal_deliver when signal_group_exit	2019-06-11 12:22:43 +02:00
smp.c	cpu/hotplug: Fix SMT supported evaluation	2018-08-15 18:14:53 +02:00
smpboot.c	kthread/smpboot: do not park in kthread_create_on_cpu()	2016-10-11 15:06:33 -07:00
smpboot.h
softirq.c	Mark HI and TASKLET softirq synchronous	2018-08-15 18:14:42 +02:00
stacktrace.c	stacktrace, lockdep: Fix address, newline ugliness	2017-02-14 15:25:42 -08:00
stop_machine.c	stop_machine: Use raw spinlocks	2018-08-03 07:55:24 +02:00
sys.c	kernel/sys.c: prctl: fix false positive in validate_prctl_map()	2019-06-22 08:17:13 +02:00
sys_ni.c	x86/pkeys: Fix pkeys build breakage for some non-x86 arches	2016-09-13 14:41:36 +02:00
sysctl.c	sysctl: return -EINVAL if val violates minmax	2019-06-22 08:17:11 +02:00
sysctl_binary.c	kernel/sysctl_binary.c: use generic UUID library	2016-05-20 17:58:30 -07:00
task_work.c	task_work: use READ_ONCE/lockless_dereference, avoid pi_lock if !task_works	2016-08-02 19:35:02 -04:00
taskstats.c	taskstats: fix the length of cgroupstats_cmd_get_policy	2016-11-03 16:55:58 -04:00
test_kprobes.c
torture.c	torture: Convert torture_shutdown() to hrtimer	2016-08-22 10:01:49 -07:00
tracepoint.c	tracepoint: Do not warn on ENOMEM	2018-05-09 09:50:20 +02:00
tsacct.c
ucount.c	kernel/ucount.c: mark user_header with kmemleak_ignore()	2017-06-17 06:41:51 +02:00
uid16.c	kernel: make groups_sort calling a responsibility group_info allocators	2018-01-10 09:29:52 +01:00
up.c	smp: Add function to execute a function synchronously on a CPU	2016-09-05 13:52:39 +02:00
user-return-notifier.c
user.c
user_namespace.c	userns: move user access out of the mutex	2018-09-09 20:01:24 +02:00
utsname.c	Merge branch 'nsfs-ioctls' into HEAD	2016-09-22 20:00:36 -05:00
utsname_sysctl.c	sys: don't hold uts_sem while accessing userspace memory	2018-09-09 20:01:24 +02:00
watchdog.c	kernel/watchdog: prevent false hardlockup on overloaded system	2017-06-17 06:41:57 +02:00
watchdog_hld.c	kernel/watchdog: prevent false hardlockup on overloaded system	2017-06-17 06:41:57 +02:00
workqueue.c	workqueue: use put_device() instead of kfree()	2018-05-30 07:50:36 +02:00
workqueue_internal.h	workqueue: Fix NULL pointer dereference	2017-11-15 15:53:17 +01:00