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| author |   Marco Elver <elver@google.com> | 2020-06-24 13:32:46 +0200 |
|---|---|---|
| committer |   Peter Zijlstra <peterz@infradead.org> | 2020-07-10 12:00:00 +0200 |
| commit | 248591f5d257a19c1cba9ab9da3536bfbc2f0149 (patch) | |
| tree | a47dc069b160aea78d3fbb9f255c2cff5b3a7942 /kernel/kcsan/report.c | |
| parent | Merge branch 'tip/x86/entry' (diff) | |
| download | linux-dev-248591f5d257a19c1cba9ab9da3536bfbc2f0149.tar.xz linux-dev-248591f5d257a19c1cba9ab9da3536bfbc2f0149.zip | |
kcsan: Make KCSAN compatible with new IRQ state tracking
The new IRQ state tracking code does not honor lockdep_off(), and as
such we should again permit tracing by using non-raw functions in
core.c. Update the lockdep_off() comment in report.c, to reflect the
fact there is still a potential risk of deadlock due to using printk()
from scheduler code.
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200624113246.GA170324@elver.google.com
Diffstat (limited to 'kernel/kcsan/report.c')
| -rw-r--r-- | kernel/kcsan/report.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/kernel/kcsan/report.c b/kernel/kcsan/report.c index ac5f8345bae9..6b2fb1a6d8cd 100644 --- a/kernel/kcsan/report.c +++ b/kernel/kcsan/report.c @@ -606,10 +606,11 @@ void kcsan_report(const volatile void *ptr, size_t size, int access_type, goto out; /* - * With TRACE_IRQFLAGS, lockdep's IRQ trace state becomes corrupted if - * we do not turn off lockdep here; this could happen due to recursion - * into lockdep via KCSAN if we detect a race in utilities used by - * lockdep. + * Because we may generate reports when we're in scheduler code, the use + * of printk() could deadlock. Until such time that all printing code + * called in print_report() is scheduler-safe, accept the risk, and just + * get our message out. As such, also disable lockdep to hide the + * warning, and avoid disabling lockdep for the rest of the kernel. */ lockdep_off(); |