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| author | Sechang Lim <rhkrqnwk98@gmail.com> | 2026-04-07 10:38:23 +0000 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-04-10 12:10:06 -0700 |
| commit | 4406942e65ca128c56c67443832988873c21d2e9 (patch) | |
| tree | 651caef99f01b8feaced9a46768c4a0618c2c791 /kernel/bpf/arraymap.c | |
| parent | ae1a82e5112e568f66cbbf2a15ea103940138dee (diff) | |
| download | linux-4406942e65ca128c56c67443832988873c21d2e9.tar.gz linux-4406942e65ca128c56c67443832988873c21d2e9.zip | |
bpf: Fix RCU stall in bpf_fd_array_map_clear()
Add a missing cond_resched() in bpf_fd_array_map_clear() loop.
For PROG_ARRAY maps with many entries this loop calls
prog_array_map_poke_run() per entry which can be expensive, and
without yielding this can cause RCU stalls under load:
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 30932 Comm: kworker/0:2 Not tainted 6.14.0-13195-g967e8def1100 #2 PREEMPT(undef)
Workqueue: events prog_array_map_clear_deferred
RIP: 0010:write_comp_data+0x38/0x90 kernel/kcov.c:246
Call Trace:
<TASK>
prog_array_map_poke_run+0x77/0x380 kernel/bpf/arraymap.c:1096
__fd_array_map_delete_elem+0x197/0x310 kernel/bpf/arraymap.c:925
bpf_fd_array_map_clear kernel/bpf/arraymap.c:1000 [inline]
prog_array_map_clear_deferred+0x119/0x1b0 kernel/bpf/arraymap.c:1141
process_one_work+0x898/0x19d0 kernel/workqueue.c:3238
process_scheduled_works kernel/workqueue.c:3319 [inline]
worker_thread+0x770/0x10b0 kernel/workqueue.c:3400
kthread+0x465/0x880 kernel/kthread.c:464
ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x19/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Reviewed-by: Sun Jian <sun.jian.kdev@gmail.com>
Fixes: da765a2f5993 ("bpf: Add poke dependency tracking for prog array maps")
Signed-off-by: Sechang Lim <rhkrqnwk98@gmail.com>
Link: https://lore.kernel.org/r/20260407103823.3942156-1-rhkrqnwk98@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf/arraymap.c')
| -rw-r--r-- | kernel/bpf/arraymap.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index 33de68c95ad8..5e25e0353509 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -1015,8 +1015,10 @@ static void bpf_fd_array_map_clear(struct bpf_map *map, bool need_defer) struct bpf_array *array = container_of(map, struct bpf_array, map); int i; - for (i = 0; i < array->map.max_entries; i++) + for (i = 0; i < array->map.max_entries; i++) { __fd_array_map_delete_elem(map, &i, need_defer); + cond_resched(); + } } static void prog_array_map_seq_show_elem(struct bpf_map *map, void *key, |