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| author | Masami Hiramatsu (Google) <mhiramat@kernel.org> | 2026-05-07 10:46:29 +0300 |
|---|---|---|
| committer | Masami Hiramatsu (Google) <mhiramat@kernel.org> | 2026-05-11 13:04:46 +0300 |
| commit | 657b594b2084b39a4bc6d8493aa2140cb00cea49 (patch) | |
| tree | fbd93b60af268e2e7b67a507a7fdd33f412e9d14 /include/linux | |
| parent | ef5581bb30efb939cc2bf093475c6cc85258e5cd (diff) | |
| download | linux-657b594b2084b39a4bc6d8493aa2140cb00cea49.tar.xz | |
fprobe: Fix unregister_fprobe() to wait for RCU grace period
Commit 4346ba1604093 ("fprobe: Rewrite fprobe on function-graph tracer")
changed fprobe to register struct fprobe to an rcu-hlist, but it forgot
to wait for RCU GP. Thus there can be use-after-free if the fprobe is
released right after unregistering. This can be happened on fprobe
event and sample module code.
To fix this issue, add synchronize_rcu() in unregister_fprobe().
Note that BPF is OK because fprobe is used as a part of
bpf_kprobe_multi_link. This unregisters its fprobe in
bpf_kprobe_multi_link_release() and it is deallocated via
bpf_kprobe_multi_link_dealloc(), which is invoked from
bpf_link_defer_dealloc_rcu_gp() RCU callback.
For BPF, this also introduced unregister_fprobe_async() which does
NOT wait for RCU grace priod.
Link: https://lore.kernel.org/all/177813998919.256460.2809243930741138224.stgit@mhiramat.tok.corp.google.com/
Fixes: 4346ba1604093 ("fprobe: Rewrite fprobe on function-graph tracer")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/fprobe.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/fprobe.h b/include/linux/fprobe.h index 0a3bcd1718f3..be1b38c981d4 100644 --- a/include/linux/fprobe.h +++ b/include/linux/fprobe.h @@ -94,6 +94,7 @@ int register_fprobe(struct fprobe *fp, const char *filter, const char *notfilter int register_fprobe_ips(struct fprobe *fp, unsigned long *addrs, int num); int register_fprobe_syms(struct fprobe *fp, const char **syms, int num); int unregister_fprobe(struct fprobe *fp); +int unregister_fprobe_async(struct fprobe *fp); bool fprobe_is_registered(struct fprobe *fp); int fprobe_count_ips_from_filter(const char *filter, const char *notfilter); #else @@ -113,6 +114,10 @@ static inline int unregister_fprobe(struct fprobe *fp) { return -EOPNOTSUPP; } +static inline int unregister_fprobe_async(struct fprobe *fp) +{ + return -EOPNOTSUPP; +} static inline bool fprobe_is_registered(struct fprobe *fp) { return false; |