diff options
| author | Ze Gao <[email protected]> | 2023-05-17 11:45:07 +0800 |
|---|---|---|
| committer | Masami Hiramatsu (Google) <[email protected]> | 2023-05-18 07:08:01 +0900 |
| commit | 3cc4e2c5fbae84e5033723fb7e350bc6c164e3a2 (patch) | |
| tree | bdfa56f3c4aacd137f1b7e4331463574c0e54a70 /lib/mpi/mpi-mod.c | |
| parent | be243bacfb25f5219f2396d787408e8cf1301dd1 (diff) | |
fprobe: make fprobe_kprobe_handler recursion free
Current implementation calls kprobe related functions before doing
ftrace recursion check in fprobe_kprobe_handler, which opens door
to kernel crash due to stack recursion if preempt_count_{add, sub}
is traceable in kprobe_busy_{begin, end}.
Things goes like this without this patch quoted from Steven:
"
fprobe_kprobe_handler() {
kprobe_busy_begin() {
preempt_disable() {
preempt_count_add() { <-- trace
fprobe_kprobe_handler() {
[ wash, rinse, repeat, CRASH!!! ]
"
By refactoring the common part out of fprobe_kprobe_handler and
fprobe_handler and call ftrace recursion detection at the very beginning,
the whole fprobe_kprobe_handler is free from recursion.
[ Fix the indentation of __fprobe_handler() parameters. ]
Link: https://lore.kernel.org/all/[email protected]/
Fixes: ab51e15d535e ("fprobe: Introduce FPROBE_FL_KPROBE_SHARED flag for fprobe")
Signed-off-by: Ze Gao <[email protected]>
Acked-by: Masami Hiramatsu (Google) <[email protected]>
Cc: [email protected]
Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
Diffstat (limited to 'lib/mpi/mpi-mod.c')
0 files changed, 0 insertions, 0 deletions