diff options
| author | David Ruth <druth@chromium.org> | 2024-06-14 22:03:26 +0300 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2024-06-18 13:28:01 +0300 |
| commit | d864319871b05fadd153e0aede4811ca7008f5d6 (patch) | |
| tree | dc7997751ce736110f9b4fec0774ca68ae964d5d /net/sched/act_api.c | |
| parent | 0271d28941cc8424f7979da692dea525f9fe1be9 (diff) | |
| download | linux-d864319871b05fadd153e0aede4811ca7008f5d6.tar.xz | |
net/sched: act_api: fix possible infinite loop in tcf_idr_check_alloc()
syzbot found hanging tasks waiting on rtnl_lock [1]
A reproducer is available in the syzbot bug.
When a request to add multiple actions with the same index is sent, the
second request will block forever on the first request. This holds
rtnl_lock, and causes tasks to hang.
Return -EAGAIN to prevent infinite looping, while keeping documented
behavior.
[1]
INFO: task kworker/1:0:5088 blocked for more than 143 seconds.
Not tainted 6.9.0-rc4-syzkaller-00173-g3cdb45594619 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:0 state:D stack:23744 pid:5088 tgid:5088 ppid:2 flags:0x00004000
Workqueue: events_power_efficient reg_check_chans_work
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5409 [inline]
__schedule+0xf15/0x5d00 kernel/sched/core.c:6746
__schedule_loop kernel/sched/core.c:6823 [inline]
schedule+0xe7/0x350 kernel/sched/core.c:6838
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6895
__mutex_lock_common kernel/locking/mutex.c:684 [inline]
__mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752
wiphy_lock include/net/cfg80211.h:5953 [inline]
reg_leave_invalid_chans net/wireless/reg.c:2466 [inline]
reg_check_chans_work+0x10a/0x10e0 net/wireless/reg.c:2481
Fixes: 0190c1d452a9 ("net: sched: atomically check-allocate action")
Reported-by: syzbot+b87c222546179f4513a7@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=b87c222546179f4513a7
Signed-off-by: David Ruth <druth@chromium.org>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://lore.kernel.org/r/20240614190326.1349786-1-druth@chromium.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net/sched/act_api.c')
| -rw-r--r-- | net/sched/act_api.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/net/sched/act_api.c b/net/sched/act_api.c index 9ee622fb1160..2520708b06a1 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -830,7 +830,6 @@ int tcf_idr_check_alloc(struct tc_action_net *tn, u32 *index, u32 max; if (*index) { -again: rcu_read_lock(); p = idr_find(&idrinfo->action_idr, *index); @@ -839,7 +838,7 @@ again: * index but did not assign the pointer yet. */ rcu_read_unlock(); - goto again; + return -EAGAIN; } if (!p) { |