| Message ID | 20230123084552.574396-1-edumazet@google.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | ea4fdbaa2f7798cb25adbe4fd52ffc6356f097bb |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] net/sched: sch_taprio: do not schedule in taprio_reset() | expand |
Hello: This patch was applied to netdev/net.git (master) by Jakub Kicinski <kuba@kernel.org>: On Mon, 23 Jan 2023 08:45:52 +0000 you wrote: > As reported by syzbot and hinted by Vinicius, I should not have added > a qdisc_synchronize() call in taprio_reset() > > taprio_reset() can be called with qdisc spinlock held (and BH disabled) > as shown in included syzbot report [1]. > > Only taprio_destroy() needed this synchronization, as explained > in the blamed commit changelog. > > [...] Here is the summary with links: - [net] net/sched: sch_taprio: do not schedule in taprio_reset() https://git.kernel.org/netdev/net/c/ea4fdbaa2f77 You are awesome, thank you!
diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index 9a11a499ea2df8d18c9c062496fdcbcf5a861391..c322a61eaeeac4b3744ec7b347d1256a19dfb244 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1700,7 +1700,6 @@ static void taprio_reset(struct Qdisc *sch) int i; hrtimer_cancel(&q->advance_timer); - qdisc_synchronize(sch); if (q->qdiscs) { for (i = 0; i < dev->num_tx_queues; i++)
As reported by syzbot and hinted by Vinicius, I should not have added a qdisc_synchronize() call in taprio_reset() taprio_reset() can be called with qdisc spinlock held (and BH disabled) as shown in included syzbot report [1]. Only taprio_destroy() needed this synchronization, as explained in the blamed commit changelog. [1] BUG: scheduling while atomic: syz-executor150/5091/0x00000202 2 locks held by syz-executor150/5091: Modules linked in: Preemption disabled at: [<0000000000000000>] 0x0 Kernel panic - not syncing: scheduling while atomic: panic_on_warn set ... CPU: 1 PID: 5091 Comm: syz-executor150 Not tainted 6.2.0-rc3-syzkaller-00219-g010a74f52203 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106 panic+0x2cc/0x626 kernel/panic.c:318 check_panic_on_warn.cold+0x19/0x35 kernel/panic.c:238 __schedule_bug.cold+0xd5/0xfe kernel/sched/core.c:5836 schedule_debug kernel/sched/core.c:5865 [inline] __schedule+0x34e4/0x5450 kernel/sched/core.c:6500 schedule+0xde/0x1b0 kernel/sched/core.c:6682 schedule_timeout+0x14e/0x2a0 kernel/time/timer.c:2167 schedule_timeout_uninterruptible kernel/time/timer.c:2201 [inline] msleep+0xb6/0x100 kernel/time/timer.c:2322 qdisc_synchronize include/net/sch_generic.h:1295 [inline] taprio_reset+0x93/0x270 net/sched/sch_taprio.c:1703 qdisc_reset+0x10c/0x770 net/sched/sch_generic.c:1022 dev_reset_queue+0x92/0x130 net/sched/sch_generic.c:1285 netdev_for_each_tx_queue include/linux/netdevice.h:2464 [inline] dev_deactivate_many+0x36d/0x9f0 net/sched/sch_generic.c:1351 dev_deactivate+0xed/0x1b0 net/sched/sch_generic.c:1374 qdisc_graft+0xe4a/0x1380 net/sched/sch_api.c:1080 tc_modify_qdisc+0xb6b/0x19a0 net/sched/sch_api.c:1689 rtnetlink_rcv_msg+0x43e/0xca0 net/core/rtnetlink.c:6141 netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2564 netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline] netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1356 netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1932 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg+0xd3/0x120 net/socket.c:734 ____sys_sendmsg+0x712/0x8c0 net/socket.c:2476 ___sys_sendmsg+0x110/0x1b0 net/socket.c:2530 __sys_sendmsg+0xf7/0x1c0 net/socket.c:2559 do_syscall_x64 arch/x86/entry/common.c:50 [inline] Fixes: 3a415d59c1db ("net/sched: sch_taprio: fix possible use-after-free") Link: https://lore.kernel.org/netdev/167387581653.2747.13878941339893288655.git-patchwork-notify@kernel.org/T/ Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Vinicius Costa Gomes <vinicius.gomes@intel.com> --- net/sched/sch_taprio.c | 1 - 1 file changed, 1 deletion(-)