diff options
| author | Noorain Eqbal <nooraineqbal@gmail.com> | 2025-10-20 23:33:01 +0530 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2025-10-21 09:57:48 -0700 |
| commit | 4e9077638301816a7d73fa1e1b4c1db4a7e3b59c (patch) | |
| tree | e2b039af8ceee0b2ef1ebe7e4145d121bcc63484 /kernel/bpf/ringbuf.c | |
| parent | 6548d364a3e850326831799d7e3ea2d7bb97ba08 (diff) | |
bpf: Sync pending IRQ work before freeing ring buffer
Fix a race where irq_work can be queued in bpf_ringbuf_commit()
but the ring buffer is freed before the work executes.
In the syzbot reproducer, a BPF program attached to sched_switch
triggers bpf_ringbuf_commit(), queuing an irq_work. If the ring buffer
is freed before this work executes, the irq_work thread may accesses
freed memory.
Calling `irq_work_sync(&rb->work)` ensures that all pending irq_work
complete before freeing the buffer.
Fixes: 457f44363a88 ("bpf: Implement BPF ring buffer and verifier support for it")
Reported-by: syzbot+2617fc732430968b45d2@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=2617fc732430968b45d2
Tested-by: syzbot+2617fc732430968b45d2@syzkaller.appspotmail.com
Signed-off-by: Noorain Eqbal <nooraineqbal@gmail.com>
Link: https://lore.kernel.org/r/20251020180301.103366-1-nooraineqbal@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf/ringbuf.c')
| -rw-r--r-- | kernel/bpf/ringbuf.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/bpf/ringbuf.c b/kernel/bpf/ringbuf.c index 719d73299397..d706c4b7f532 100644 --- a/kernel/bpf/ringbuf.c +++ b/kernel/bpf/ringbuf.c @@ -216,6 +216,8 @@ static struct bpf_map *ringbuf_map_alloc(union bpf_attr *attr) static void bpf_ringbuf_free(struct bpf_ringbuf *rb) { + irq_work_sync(&rb->work); + /* copy pages pointer and nr_pages to local variable, as we are going * to unmap rb itself with vunmap() below */ |