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author | Sven Schnelle <svens@linux.ibm.com> | 2019-12-09 11:03:12 +0300 |
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committer | Vasily Gorbik <gor@linux.ibm.com> | 2019-12-19 01:29:26 +0300 |
commit | 6feeee8efc53035c3195b02068b58ae947538aa4 (patch) | |
tree | 7d7e00a80b7725e5664d44809f83b5674723528d /arch/s390/purgatory/Makefile | |
parent | d1eef1c619749b2a57e514a3fa67d9a516ffa919 (diff) | |
download | linux-6feeee8efc53035c3195b02068b58ae947538aa4.tar.xz |
s390/ftrace: fix endless recursion in function_graph tracer
The following sequence triggers a kernel stack overflow on s390x:
mount -t tracefs tracefs /sys/kernel/tracing
cd /sys/kernel/tracing
echo function_graph > current_tracer
[crash]
This is because preempt_count_{add,sub} are in the list of traced
functions, which can be demonstrated by:
echo preempt_count_add >set_ftrace_filter
echo function_graph > current_tracer
[crash]
The stack overflow happens because get_tod_clock_monotonic() gets called
by ftrace but itself calls preempt_{disable,enable}(), which leads to a
endless recursion. Fix this by using preempt_{disable,enable}_notrace().
Fixes: 011620688a71 ("s390/time: ensure get_clock_monotonic() returns monotonic values")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390/purgatory/Makefile')
0 files changed, 0 insertions, 0 deletions