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| author | Paul E. McKenney <paulmck@kernel.org> | 2020-06-30 13:22:54 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2020-09-04 11:52:50 -0700 |
| commit | 35feb60474bf4f7fa7840e14fc7fd344996b919d (patch) | |
| tree | 17030fd8b9c654eab6b9da001de1776ff95a2385 /lib | |
| parent | e48c15b796d412ede883bb2ef7779b2a142f7962 (diff) | |
| download | linux-35feb60474bf4f7fa7840e14fc7fd344996b919d.tar.gz linux-35feb60474bf4f7fa7840e14fc7fd344996b919d.tar.bz2 linux-35feb60474bf4f7fa7840e14fc7fd344996b919d.zip | |
kernel/smp: Provide CSD lock timeout diagnostics
This commit causes csd_lock_wait() to emit diagnostics when a CPU
fails to respond quickly enough to one of the smp_call_function()
family of function calls. These diagnostics are enabled by a new
CSD_LOCK_WAIT_DEBUG Kconfig option that depends on DEBUG_KERNEL.
This commit was inspired by an earlier patch by Josef Bacik.
[ paulmck: Fix for syzbot+0f719294463916a3fc0e@syzkaller.appspotmail.com ]
[ paulmck: Fix KASAN use-after-free issue reported by Qian Cai. ]
[ paulmck: Fix botched nr_cpu_ids comparison per Dan Carpenter. ]
[ paulmck: Apply Peter Zijlstra feedback. ]
Link: https://lore.kernel.org/lkml/00000000000042f21905a991ecea@google.com
Link: https://lore.kernel.org/lkml/0000000000002ef21705a9933cf3@google.com
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig.debug | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index e068c3c7189a..86a35fdfe021 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1367,6 +1367,17 @@ config WW_MUTEX_SELFTEST Say M if you want these self tests to build as a module. Say N if you are unsure. +config CSD_LOCK_WAIT_DEBUG + bool "Debugging for csd_lock_wait(), called from smp_call_function*()" + depends on DEBUG_KERNEL + depends on 64BIT + default n + help + This option enables debug prints when CPUs are slow to respond + to the smp_call_function*() IPI wrappers. These debug prints + include the IPI handler function currently executing (if any) + and relevant stack traces. + endmenu # lock debugging config TRACE_IRQFLAGS |