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authorSong Liu <song@kernel.org>2022-07-29 21:41:06 +0200
committerAndrii Nakryiko <andrii@kernel.org>2022-07-29 23:20:29 +0200
commitdc81f8d1e8ea3f5dfa88919cb834a135a6a536b8 (patch)
tree768396ce424885c8a66b3fadb7b348195b236199 /kernel/bpf/trampoline.c
parentselftests/bpf: Bump internal send_signal/send_signal_tracepoint timeout (diff)
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bpf: Fix test_progs -j error with fentry/fexit tests
When multiple threads are attaching/detaching fentry/fexit programs to the same trampoline, we may call register_fentry on the same trampoline twice: register_fentry(), unregister_fentry(), then register_fentry again. This causes ftrace_set_filter_ip() for the same ip on tr->fops twice, which leaves duplicated ip in tr->fops. The extra ip is not cleaned up properly on unregister and thus causes failures with further register in register_ftrace_direct_multi(): register_ftrace_direct_multi() { ... for (i = 0; i < size; i++) { hlist_for_each_entry(entry, &hash->buckets[i], hlist) { if (ftrace_find_rec_direct(entry->ip)) goto out_unlock; } } ... } This can be triggered with parallel fentry/fexit tests with test_progs: ./test_progs -t fentry,fexit -j Fix this by resetting tr->fops in ftrace_set_filter_ip(), so that there will never be duplicated entries in tr->fops. Fixes: 00963a2e75a8 ("bpf: Support bpf_trampoline on functions with IPMODIFY (e.g. livepatch)") Reported-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Song Liu <song@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220729194106.1207472-1-song@kernel.org
Diffstat (limited to '')
-rw-r--r--kernel/bpf/trampoline.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index 42e387a12694..7ec7e23559ad 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -255,7 +255,7 @@ static int register_fentry(struct bpf_trampoline *tr, void *new_addr)
return -ENOENT;
if (tr->func.ftrace_managed) {
- ftrace_set_filter_ip(tr->fops, (unsigned long)ip, 0, 0);
+ ftrace_set_filter_ip(tr->fops, (unsigned long)ip, 0, 1);
ret = register_ftrace_direct_multi(tr->fops, (long)new_addr);
} else {
ret = bpf_arch_text_poke(ip, BPF_MOD_CALL, NULL, new_addr);