* Re: [syzbot] [batman?] [bpf?] possible deadlock in lock_timer_base
[not found] <000000000000c0645805b7f982e4@google.com>
@ 2024-03-19 10:33 ` syzbot
2024-03-19 13:19 ` Sven Eckelmann
0 siblings, 1 reply; 3+ messages in thread
From: syzbot @ 2024-03-19 10:33 UTC (permalink / raw)
To: a, akpm, andrii, ast, b.a.t.m.a.n, bpf, christian, daniel, davem,
dvyukov, edumazet, elver, glider, hdanton, jakub, jannh,
john.fastabend, kasan-dev, kuba, linux-kernel, linux-mm,
mareklindner, mark.rutland, netdev, pabeni, shakeelb, sven, sw,
syzkaller-bugs
syzbot has found a reproducer for the following issue on:
HEAD commit: 35c3e2791756 Revert "net: Re-use and set mono_delivery_tim..
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=10569181180000
kernel config: https://syzkaller.appspot.com/x/.config?x=6fb1be60a193d440
dashboard link: https://syzkaller.appspot.com/bug?extid=8983d6d4f7df556be565
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13d9fa4e180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=137afac9180000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/26b55a26fc12/disk-35c3e279.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6f39fa55c828/vmlinux-35c3e279.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e1e0501539e6/bzImage-35c3e279.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8983d6d4f7df556be565@syzkaller.appspotmail.com
=====================================================
WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected
6.8.0-syzkaller-05228-g35c3e2791756 #0 Not tainted
-----------------------------------------------------
rcu_preempt/16 [HC0[0]:SC0[2]:HE0:SE0] is trying to acquire:
ffff888021c65020 (&htab->buckets[i].lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff888021c65020 (&htab->buckets[i].lock){+...}-{2:2}, at: sock_hash_delete_elem+0xb0/0x300 net/core/sock_map.c:939
and this task is already holding:
ffff8880b952a758
(&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x112/0x240 kernel/time/timer.c:1051
which would create a new lock dependency:
(&base->lock){-.-.}-{2:2} -> (
&htab->buckets[i].lock){+...}-{2:2}
but this new dependency connects a HARDIRQ-irq-safe lock:
(&base->lock){-.-.}-{2:2}
... which became HARDIRQ-irq-safe at:
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
lock_timer_base+0x112/0x240 kernel/time/timer.c:1051
add_timer_on+0x1e5/0x5c0 kernel/time/timer.c:1366
handle_irq_event_percpu kernel/irq/handle.c:195 [inline]
handle_irq_event+0xad/0x1f0 kernel/irq/handle.c:210
handle_level_irq+0x3c5/0x6e0 kernel/irq/chip.c:648
generic_handle_irq_desc include/linux/irqdesc.h:161 [inline]
handle_irq arch/x86/kernel/irq.c:238 [inline]
__common_interrupt+0x13a/0x230 arch/x86/kernel/irq.c:257
common_interrupt+0xa5/0xd0 arch/x86/kernel/irq.c:247
asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
_raw_spin_unlock_irqrestore+0xd8/0x140 kernel/locking/spinlock.c:194
__setup_irq+0x1277/0x1cf0 kernel/irq/manage.c:1818
request_threaded_irq+0x2ab/0x380 kernel/irq/manage.c:2202
request_irq include/linux/interrupt.h:168 [inline]
setup_default_timer_irq+0x25/0x60 arch/x86/kernel/time.c:70
x86_late_time_init+0x66/0xc0 arch/x86/kernel/time.c:94
start_kernel+0x3f3/0x500 init/main.c:1039
x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:509
x86_64_start_kernel+0x99/0xa0 arch/x86/kernel/head64.c:490
common_startup_64+0x13e/0x147
to a HARDIRQ-irq-unsafe lock:
(&htab->buckets[i].lock){+...}-{2:2}
... which became HARDIRQ-irq-unsafe at:
...
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
sock_hash_free+0x164/0x820 net/core/sock_map.c:1154
bpf_map_free_deferred+0xe6/0x110 kernel/bpf/syscall.c:734
process_one_work kernel/workqueue.c:3254 [inline]
process_scheduled_works+0xa00/0x1770 kernel/workqueue.c:3335
worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
kthread+0x2f0/0x390 kernel/kthread.c:388
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
other info that might help us debug this:
Possible interrupt unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&htab->buckets[i].lock
);
local_irq_disable();
lock(&base->lock);
lock(&htab->buckets[i].lock
);
<Interrupt>
lock(&base->lock);
*** DEADLOCK ***
2 locks held by rcu_preempt/16:
#0:
ffff8880b952a758
(&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x112/0x240 kernel/time/timer.c:1051
#1: ffffffff8e131920
(rcu_read_lock
){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline]
){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline]
){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2380 [inline]
){....}-{1:2}, at: bpf_trace_run2+0x114/0x420 kernel/trace/bpf_trace.c:2420
the dependencies between HARDIRQ-irq-safe lock and the holding lock:
-> (&base->lock){-.-.}-{2:2} {
IN-HARDIRQ-W at:
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
lock_timer_base+0x112/0x240 kernel/time/timer.c:1051
add_timer_on+0x1e5/0x5c0 kernel/time/timer.c:1366
handle_irq_event_percpu kernel/irq/handle.c:195 [inline]
handle_irq_event+0xad/0x1f0 kernel/irq/handle.c:210
handle_level_irq+0x3c5/0x6e0 kernel/irq/chip.c:648
generic_handle_irq_desc include/linux/irqdesc.h:161 [inline]
handle_irq arch/x86/kernel/irq.c:238 [inline]
__common_interrupt+0x13a/0x230 arch/x86/kernel/irq.c:257
common_interrupt+0xa5/0xd0 arch/x86/kernel/irq.c:247
asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
_raw_spin_unlock_irqrestore+0xd8/0x140 kernel/locking/spinlock.c:194
__setup_irq+0x1277/0x1cf0 kernel/irq/manage.c:1818
request_threaded_irq+0x2ab/0x380 kernel/irq/manage.c:2202
request_irq include/linux/interrupt.h:168 [inline]
setup_default_timer_irq+0x25/0x60 arch/x86/kernel/time.c:70
x86_late_time_init+0x66/0xc0 arch/x86/kernel/time.c:94
start_kernel+0x3f3/0x500 init/main.c:1039
x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:509
x86_64_start_kernel+0x99/0xa0 arch/x86/kernel/head64.c:490
common_startup_64+0x13e/0x147
IN-SOFTIRQ-W at:
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
_raw_spin_lock_irq+0xd3/0x120 kernel/locking/spinlock.c:170
__run_timer_base+0x103/0x8e0 kernel/time/timer.c:2418
run_timer_base kernel/time/timer.c:2428 [inline]
run_timer_softirq+0x67/0x170 kernel/time/timer.c:2436
__do_softirq+0x2be/0x943 kernel/softirq.c:554
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu+0xf2/0x1c0 kernel/softirq.c:633
irq_exit_rcu+0x9/0x30 kernel/softirq.c:645
common_interrupt+0xaa/0xd0 arch/x86/kernel/irq.c:247
asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
console_flush_all+0x9cd/0xec0
console_unlock+0x13b/0x4d0 kernel/printk/printk.c:3025
vprintk_emit+0x509/0x720 kernel/printk/printk.c:2292
_printk+0xd5/0x120 kernel/printk/printk.c:2317
cpu_select_mitigations+0x3c/0xa0 arch/x86/kernel/cpu/bugs.c:148
arch_cpu_finalize_init+0x20/0xa0 arch/x86/kernel/cpu/common.c:2325
start_kernel+0x402/0x500 init/main.c:1043
x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:509
x86_64_start_kernel+0x99/0xa0 arch/x86/kernel/head64.c:490
common_startup_64+0x13e/0x147
INITIAL USE
at:
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
lock_timer_base+0x112/0x240 kernel/time/timer.c:1051
__mod_timer+0x1ca/0xeb0 kernel/time/timer.c:1132
queue_delayed_work_on+0x15a/0x260 kernel/workqueue.c:2595
queue_delayed_work include/linux/workqueue.h:620 [inline]
crng_reseed+0xe7/0x220 drivers/char/random.c:258
random_init+0x1a9/0x300 drivers/char/random.c:901
start_kernel+0x253/0x500 init/main.c:991
x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:509
x86_64_start_kernel+0x99/0xa0 arch/x86/kernel/head64.c:490
common_startup_64+0x13e/0x147
}
... key at: [<ffffffff945023c0>] init_timer_cpu.__key+0x0/0x20
the dependencies between the lock to be acquired
and HARDIRQ-irq-unsafe lock:
->
(&htab->buckets[i].lock
){+...}-{2:2} {
HARDIRQ-ON-W at:
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
sock_hash_free+0x164/0x820 net/core/sock_map.c:1154
bpf_map_free_deferred+0xe6/0x110 kernel/bpf/syscall.c:734
process_one_work kernel/workqueue.c:3254 [inline]
process_scheduled_works+0xa00/0x1770 kernel/workqueue.c:3335
worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
kthread+0x2f0/0x390 kernel/kthread.c:388
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
INITIAL USE
at:
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
sock_hash_free+0x164/0x820 net/core/sock_map.c:1154
bpf_map_free_deferred+0xe6/0x110 kernel/bpf/syscall.c:734
process_one_work kernel/workqueue.c:3254 [inline]
process_scheduled_works+0xa00/0x1770 kernel/workqueue.c:3335
worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
kthread+0x2f0/0x390 kernel/kthread.c:388
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
}
... key at: [<ffffffff94882300>] sock_hash_alloc.__key+0x0/0x20
... acquired at:
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
sock_hash_delete_elem+0xb0/0x300 net/core/sock_map.c:939
bpf_prog_2c29ac5cdc6b1842+0x42/0x46
bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
__bpf_prog_run include/linux/filter.h:657 [inline]
bpf_prog_run include/linux/filter.h:664 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
bpf_trace_run2+0x204/0x420 kernel/trace/bpf_trace.c:2420
trace_timer_start include/trace/events/timer.h:52 [inline]
enqueue_timer+0x396/0x550 kernel/time/timer.c:663
internal_add_timer kernel/time/timer.c:688 [inline]
__mod_timer+0xa0e/0xeb0 kernel/time/timer.c:1183
schedule_timeout+0x1b9/0x310 kernel/time/timer.c:2571
rcu_gp_fqs_loop+0x2df/0x1370 kernel/rcu/tree.c:1663
rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:1862
kthread+0x2f0/0x390 kernel/kthread.c:388
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
stack backtrace:
CPU: 1 PID: 16 Comm: rcu_preempt Not tainted 6.8.0-syzkaller-05228-g35c3e2791756 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106
print_bad_irq_dependency kernel/locking/lockdep.c:2626 [inline]
check_irq_usage kernel/locking/lockdep.c:2865 [inline]
check_prev_add kernel/locking/lockdep.c:3138 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain+0x4dc7/0x58e0 kernel/locking/lockdep.c:3869
__lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
sock_hash_delete_elem+0xb0/0x300 net/core/sock_map.c:939
bpf_prog_2c29ac5cdc6b1842+0x42/0x46
bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
__bpf_prog_run include/linux/filter.h:657 [inline]
bpf_prog_run include/linux/filter.h:664 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
bpf_trace_run2+0x204/0x420 kernel/trace/bpf_trace.c:2420
trace_timer_start include/trace/events/timer.h:52 [inline]
enqueue_timer+0x396/0x550 kernel/time/timer.c:663
internal_add_timer kernel/time/timer.c:688 [inline]
__mod_timer+0xa0e/0xeb0 kernel/time/timer.c:1183
schedule_timeout+0x1b9/0x310 kernel/time/timer.c:2571
rcu_gp_fqs_loop+0x2df/0x1370 kernel/rcu/tree.c:1663
rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:1862
kthread+0x2f0/0x390 kernel/kthread.c:388
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
</TASK>
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
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