[v5.15] BUG: soft lockup in tc_modify_qdisc

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0ab06468cbd1 Linux 5.15.114
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1270f095280000
kernel config: https://syzkaller.appspot.com/x/.config?x=9a2696a271d0eba
dashboard link: https://syzkaller.appspot.com/bug?extid=510305eb6a4bd79f22df
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12ddb42d280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=120fb659280000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8ff3613d3f6b/disk-0ab06468.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/eebe2d8c6813/vmlinux-0ab06468.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f30284c26197/Image-0ab06468.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+510305...@syzkaller.appspotmail.com

watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [syz-executor116:4054]
Modules linked in:
irq event stamp: 5259
hardirqs last enabled at (5258): [<ffff800011947a48>] __exit_to_kernel_mode arch/arm64/kernel/entry-common.c:81 [inline]
hardirqs last enabled at (5258): [<ffff800011947a48>] exit_to_kernel_mode+0x100/0x178 arch/arm64/kernel/entry-common.c:91
hardirqs last disabled at (5259): [<ffff800011947c90>] enter_el1_irq_or_nmi+0x10/0x1c arch/arm64/kernel/entry-common.c:227
softirqs last enabled at (510): [<ffff80000fd894b4>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:31
softirqs last disabled at (514): [<ffff800010094f44>] fq_pie_change+0x248/0xda8 net/sched/sch_fq_pie.c:293
CPU: 0 PID: 4054 Comm: syz-executor116 Not tainted 5.15.114-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023
pstate: 00400005 (nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : queued_spin_lock_slowpath+0x160/0x938 kernel/locking/qspinlock.c:382
lr : queued_spin_lock_slowpath+0x16c/0x938 kernel/locking/qspinlock.c:382
sp : ffff80001cd76aa0
x29: ffff80001cd76b40 x28: 1ffff000039aed60 x27: 1fffe0001967b41f
x26: dfff800000000000 x25: ffff7000039aed58 x24: ffff80001cd76ac0
x23: 1fffe0001967b41e x22: ffff80001cd76b00 x21: 0000000000000001
x20: 0000000000000001 x19: ffff0000cb3da0f0 x18: 0000000000000000
x17: ff8080000aae0f20 x16: ffff80000830309c x15: ffff80000aae0f20
x14: 1ffff0000291a06a x13: ffffffffffffffff x12: 0000000000000001
x11: 1fffe0001967b41e x10: 0000000000000000 x9 : 0000000000000000
x8 : 0000000000000101 x7 : ffff800010094f44 x6 : 0000000000000000
x5 : 0000000000000000
x4 : 0000000000000001 x3 : ffff8000083023a8
x2 : 0000000000000000
x1 : 0000000000000004
x0 : 0000000000000001

Call trace:
__cmpwait_case_32 arch/arm64/include/asm/cmpxchg.h:252 [inline]
__cmpwait arch/arm64/include/asm/cmpxchg.h:278 [inline]
queued_spin_lock_slowpath+0x160/0x938 kernel/locking/qspinlock.c:382
queued_spin_lock include/asm-generic/qspinlock.h:85 [inline]
do_raw_spin_lock+0x334/0x35c kernel/locking/spinlock_debug.c:115
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:136 [inline]
_raw_spin_lock_bh+0x12c/0x1c4 kernel/locking/spinlock.c:178
fq_pie_change+0x248/0xda8 net/sched/sch_fq_pie.c:293
fq_pie_init+0x2b0/0x714 net/sched/sch_fq_pie.c:414
qdisc_create+0x61c/0x1300 net/sched/sch_api.c:1259
tc_modify_qdisc+0x8dc/0x126c
rtnetlink_rcv_msg+0xa74/0xdac net/core/rtnetlink.c:5587
netlink_rcv_skb+0x20c/0x3b8 net/netlink/af_netlink.c:2504
rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:5605
netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
netlink_unicast+0x664/0x938 net/netlink/af_netlink.c:1356
netlink_sendmsg+0x844/0xb38 net/netlink/af_netlink.c:1923
sock_sendmsg_nosec net/socket.c:704 [inline]
sock_sendmsg net/socket.c:724 [inline]
____sys_sendmsg+0x584/0x870 net/socket.c:2412
___sys_sendmsg+0x214/0x294 net/socket.c:2466
__sys_sendmsg net/socket.c:2495 [inline]
__do_sys_sendmsg net/socket.c:2504 [inline]
__se_sys_sendmsg net/socket.c:2502 [inline]
__arm64_sys_sendmsg+0x1ac/0x25c net/socket.c:2502
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584


---
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If the bug is already fixed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
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If the bug is a duplicate of another bug, reply with:
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If you want to undo deduplication, reply with:
#syz undup

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: d2869ace6eeb Linux 6.1.31
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17549eb6280000
kernel config: https://syzkaller.appspot.com/x/.config?x=11263f470b7a4c92
dashboard link: https://syzkaller.appspot.com/bug?extid=3d5bc6a437ebce408b84

compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11daef71280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10e27dd1280000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b17a7cd87498/disk-d2869ace.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/cc8291ae723a/vmlinux-d2869ace.xz
kernel image: https://storage.googleapis.com/syzbot-assets/04943541fc25/Image-d2869ace.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:

Reported-by: syzbot+3d5bc6...@syzkaller.appspotmail.com

watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [syz-executor256:4302]
Modules linked in:
irq event stamp: 5009
hardirqs last enabled at (5008): [<ffff8000120fb1c0>] __exit_to_kernel_mode arch/arm64/kernel/entry-common.c:84 [inline]
hardirqs last enabled at (5008): [<ffff8000120fb1c0>] exit_to_kernel_mode+0xe8/0x118 arch/arm64/kernel/entry-common.c:94
hardirqs last disabled at (5009): [<ffff8000120f8e9c>] __el1_irq arch/arm64/kernel/entry-common.c:468 [inline]
hardirqs last disabled at (5009): [<ffff8000120f8e9c>] el1_interrupt+0x24/0x68 arch/arm64/kernel/entry-common.c:486
softirqs last enabled at (512): [<ffff8000103f7d94>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (518): [<ffff800010711c4c>] fq_pie_change+0x23c/0xda4 net/sched/sch_fq_pie.c:290
CPU: 0 PID: 4302 Comm: syz-executor256 Not tainted 6.1.31-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023
pstate: 00400005 (nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)

pc : queued_spin_lock_slowpath+0x15c/0xe48 kernel/locking/qspinlock.c:383
lr : queued_spin_lock_slowpath+0x168/0xe48 kernel/locking/qspinlock.c:383
sp : ffff80001dcd6b60
x29: ffff80001dcd6c00 x28: 1fffe0001b28461e x27: 1ffff00003b9ad78
x26: dfff800000000000 x25: 1fffe0001b284620 x24: ffff80001dcd6b80
x23: ffff80001dcd6bc0 x22: ffff700003b9ad70 x21: 0000000000000001
x20: 0000000000000001 x19: ffff0000d94230f0 x18: ffff0000cd6b0010
x17: 0000000000000000 x16: ffff80000896d2d4 x15: 0000000000000000
x14: 1ffff00002ab80b0 x13: dfff800000000000 x12: 0000000000000001
x11: 1fffe0001b28461e x10: 0000000000000000 x9 : 0000000000000000
x8 : 0000000000000101 x7 : ffff800010711c4c x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffff8000121dcbf4

x2 : 0000000000000000 x1 : 0000000000000004 x0 : 0000000000000001
Call trace:
__cmpwait_case_32 arch/arm64/include/asm/cmpxchg.h:252 [inline]
__cmpwait arch/arm64/include/asm/cmpxchg.h:278 [inline]

queued_spin_lock_slowpath+0x15c/0xe48 kernel/locking/qspinlock.c:383
queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
do_raw_spin_lock+0x330/0x358 kernel/locking/spinlock_debug.c:115
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:127 [inline]
_raw_spin_lock_bh+0x5c/0x6c kernel/locking/spinlock.c:178
fq_pie_change+0x23c/0xda4 net/sched/sch_fq_pie.c:290
fq_pie_init+0x2b0/0x714 net/sched/sch_fq_pie.c:411
qdisc_create+0x6ac/0xde4 net/sched/sch_api.c:1277
tc_modify_qdisc+0x954/0x16c0
rtnetlink_rcv_msg+0x72c/0xd94 net/core/rtnetlink.c:6091
netlink_rcv_skb+0x20c/0x3b8 net/netlink/af_netlink.c:2524
rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6109
netlink_unicast_kernel net/netlink/af_netlink.c:1328 [inline]
netlink_unicast+0x660/0x8d4 net/netlink/af_netlink.c:1354
netlink_sendmsg+0x834/0xb18 net/netlink/af_netlink.c:1902
sock_sendmsg_nosec net/socket.c:716 [inline]
sock_sendmsg net/socket.c:736 [inline]
____sys_sendmsg+0x558/0x844 net/socket.c:2482
___sys_sendmsg net/socket.c:2536 [inline]
__sys_sendmsg+0x26c/0x33c net/socket.c:2565
__do_sys_sendmsg net/socket.c:2574 [inline]
__se_sys_sendmsg net/socket.c:2572 [inline]
__arm64_sys_sendmsg+0x80/0x94 net/socket.c:2572
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581

[syzbot]

syzbot suspects this issue was fixed by commit:

commit 1d37434ffc1376306167dc61f37f78da18455b74
Author: Eric Dumazet <edum...@google.com>
Date: Fri Jun 2 12:37:47 2023 +0000

net/sched: fq_pie: ensure reasonable TCA_FQ_PIE_QUANTUM values

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1119c7d2a80000
start commit: d2869ace6eeb Linux 6.1.31
git tree: linux-6.1.y

kernel config: https://syzkaller.appspot.com/x/.config?x=11263f470b7a4c92
dashboard link: https://syzkaller.appspot.com/bug?extid=3d5bc6a437ebce408b84

userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11daef71280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10e27dd1280000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: net/sched: fq_pie: ensure reasonable TCA_FQ_PIE_QUANTUM values

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

[syzbot]

Auto-closing this bug as obsolete.
No recent activity, existing reproducers are no longer triggering the issue.