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| author | David Ruth <druth@chromium.org> | 2024-06-14 19:03:26 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-07-05 09:12:38 +0200 |
| commit | c6a7da65a296745535a964be1019ec7691b0cb90 (patch) | |
| tree | 1346de9904568f235e4cd08c66c0f891afb20ab5 /net | |
| parent | 66c7aa157a38d93947b32c0d309889369a27e8e2 (diff) | |
| download | linux-c6a7da65a296745535a964be1019ec7691b0cb90.tar.gz linux-c6a7da65a296745535a964be1019ec7691b0cb90.tar.bz2 linux-c6a7da65a296745535a964be1019ec7691b0cb90.zip | |
net/sched: act_api: fix possible infinite loop in tcf_idr_check_alloc()
[ Upstream commit d864319871b05fadd153e0aede4811ca7008f5d6 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'net')
| -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 eb6bb90ddd33..bf98bb602a9d 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -521,7 +521,6 @@ 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); @@ -530,7 +529,7 @@ again: * index but did not assign the pointer yet. */ rcu_read_unlock(); - goto again; + return -EAGAIN; } if (!p) { |