Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
INFO: task hung in uevent_show
INFO: task udevd:4562 blocked for more than 143 seconds.
Not tainted 6.10.0-rc2-next-20240607-syzkaller-dirty #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D stack:27128 pid:4562 tgid:4562 ppid:2403 flags:0x00000002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5192 [inline]
__schedule+0xca6/0x2f50 kernel/sched/core.c:6529
__schedule_loop kernel/sched/core.c:6606 [inline]
schedule+0xe7/0x350 kernel/sched/core.c:6621
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6678
__mutex_lock_common kernel/locking/mutex.c:684 [inline]
__mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752
device_lock include/linux/device.h:1009 [inline]
uevent_show+0x188/0x3b0 drivers/base/core.c:2743
dev_attr_show+0x53/0xe0 drivers/base/core.c:2437
sysfs_kf_seq_show+0x23e/0x410 fs/sysfs/file.c:59
seq_read_iter+0x4fa/0x12c0 fs/seq_file.c:230
kernfs_fop_read_iter+0x41a/0x590 fs/kernfs/file.c:279
new_sync_read fs/read_write.c:395 [inline]
vfs_read+0x869/0xbd0 fs/read_write.c:476
ksys_read+0x12f/0x260 fs/read_write.c:619
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7546015b6a
RSP: 002b:00007ffc5026dbf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 000055873fe1dfa0 RCX: 00007f7546015b6a
RDX: 0000000000001000 RSI: 000055873fe2b950 RDI: 0000000000000008
RBP: 000055873fe1dfa0 R08: 0000000000000008 R09: 0000000000000000
R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000003fff R14: 00007ffc5026e0d8 R15: 000000000000000a
</TASK>
Showing all locks held in the system:
5 locks held by kworker/0:1/9:
1 lock held by khungtaskd/30:
#0: ffffffff886b4c20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:326 [inline]
#0: ffffffff886b4c20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff886b4c20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x75/0x340 kernel/locking/lockdep.c:6689
2 locks held by getty/2461:
#0: ffff88810e7a50a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc900000432f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xfc8/0x1490 drivers/tty/n_tty.c:2211
4 locks held by udevd/4562:
#0: ffff888119d570a0 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xde/0x12c0 fs/seq_file.c:182
#1: ffff888116049488 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154
#2: ffff88810ef83b48 (kn->active){.+.+}-{0:0}, at: kernfs_seq_start+0x71/0x240 fs/kernfs/file.c:155
#3: ffff8881042f2190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:1009 [inline]
#3: ffff8881042f2190 (&dev->mutex){....}-{3:3}, at: uevent_show+0x188/0x3b0 drivers/base/core.c:2743
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 30 Comm: khungtaskd Not tainted 6.10.0-rc2-next-20240607-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:91 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:117
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline]
watchdog+0xf86/0x1240 kernel/hung_task.c:379
kthread+0x2c1/0x3a0 kernel/kthread.c:389
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:144
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 9 Comm: kworker/0:1 Not tainted 6.10.0-rc2-next-20240607-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
Workqueue: usb_hub_wq hub_event
RIP: 0010:unwind_next_frame+0x5de/0x23a0 arch/x86/kernel/unwind_orc.c:505
Code: 6c 24 05 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 0f b6 04 02 4c 89 ea 83 e2 07 38 d0 7f 08 84 c0 0f 85 71 18 00 00 <45> 0f b6 74 24 05 31 ff 41 83 e6 07 44 89 f6 e8 2e 45 3e 00 45 84
RSP: 0018:ffffc9000009e490 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffc9000009e510 RCX: ffffffff81151bc4
RDX: 0000000000000001 RSI: ffffffff81152c52 RDI: 0000000000000006
RBP: 0000000000000001 R08: 0000000000000006 R09: ffffffff81a5ce53
R10: ffffffff81a5ce45 R11: 0000000000000005 R12: ffffffff8a1e1764
R13: ffffffff8a1e1769 R14: 00000000000278ef R15: ffffc9000009e545
FS: 0000000000000000(0000) GS:ffff8881f6400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbd876d8de0 CR3: 00000001151aa000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<TASK>
arch_stack_walk+0x100/0x170 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
__kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:387
kmalloc_noprof include/linux/slab.h:660 [inline]
dummy_urb_enqueue+0x8d/0x8a0 drivers/usb/gadget/udc/dummy_hcd.c:1271
usb_hcd_submit_urb+0x2d1/0x2090 drivers/usb/core/hcd.c:1533
usb_submit_urb+0x87c/0x1730 drivers/usb/core/urb.c:581
usb_start_wait_urb+0x103/0x4c0 drivers/usb/core/message.c:59
usb_internal_control_msg drivers/usb/core/message.c:103 [inline]
usb_control_msg+0x327/0x4b0 drivers/usb/core/message.c:154
_usbctrl_vendorreq_sync+0xc6/0x1f0 drivers/net/wireless/realtek/rtlwifi/usb.c:42
_usb_read_sync+0x11d/0x190 drivers/net/wireless/realtek/rtlwifi/usb.c:75
rtl_read_dword drivers/net/wireless/realtek/rtlwifi/wifi.h:2911 [inline]
read_efuse_byte+0x612/0x910 drivers/net/wireless/realtek/rtlwifi/efuse.c:182
read_efuse+0x9a7/0xd60 drivers/net/wireless/realtek/rtlwifi/efuse.c:282
efuse_read_all_map drivers/net/wireless/realtek/rtlwifi/efuse.c:648 [inline]
rtl_efuse_shadow_map_update+0x23b/0x2b0 drivers/net/wireless/realtek/rtlwifi/efuse.c:494
rtl_get_hwinfo+0xdb/0x880 drivers/net/wireless/realtek/rtlwifi/efuse.c:1224
_rtl92cu_read_adapter_info drivers/net/wireless/realtek/rtlwifi/rtl8192cu/hw.c:334 [inline]
rtl92cu_read_eeprom_info+0x2bc/0x2730 drivers/net/wireless/realtek/rtlwifi/rtl8192cu/hw.c:411
rtl_usb_probe+0x915/0x24d0 drivers/net/wireless/realtek/rtlwifi/usb.c:1011
usb_probe_interface+0x309/0x9d0 drivers/usb/core/driver.c:399
call_driver_probe drivers/base/dd.c:578 [inline]
really_probe+0x23e/0xa90 drivers/base/dd.c:656
__driver_probe_device+0x1de/0x440 drivers/base/dd.c:798
driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:828
__device_attach_driver+0x1df/0x310 drivers/base/dd.c:956
bus_for_each_drv+0x157/0x1e0 drivers/base/bus.c:457
__device_attach+0x1e8/0x4b0 drivers/base/dd.c:1028
bus_probe_device+0x17f/0x1c0 drivers/base/bus.c:532
device_add+0x114b/0x1a70 drivers/base/core.c:3679
usb_set_configuration+0x10cb/0x1c50 drivers/usb/core/message.c:2210
usb_generic_driver_probe+0xb1/0x110 drivers/usb/core/generic.c:254
usb_probe_device+0xec/0x3e0 drivers/usb/core/driver.c:294
call_driver_probe drivers/base/dd.c:578 [inline]
really_probe+0x23e/0xa90 drivers/base/dd.c:656
__driver_probe_device+0x1de/0x440 drivers/base/dd.c:798
driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:828
__device_attach_driver+0x1df/0x310 drivers/base/dd.c:956
bus_for_each_drv+0x157/0x1e0 drivers/base/bus.c:457
__device_attach+0x1e8/0x4b0 drivers/base/dd.c:1028
bus_probe_device+0x17f/0x1c0 drivers/base/bus.c:532
device_add+0x114b/0x1a70 drivers/base/core.c:3679
usb_new_device+0xd90/0x1a10 drivers/usb/core/hub.c:2651
hub_port_connect drivers/usb/core/hub.c:5521 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5661 [inline]
port_event drivers/usb/core/hub.c:5821 [inline]
hub_event+0x2e66/0x4f50 drivers/usb/core/hub.c:5903
process_one_work+0x9fb/0x1b60 kernel/workqueue.c:3248
process_scheduled_works kernel/workqueue.c:3329 [inline]
worker_thread+0x6c8/0xf30 kernel/workqueue.c:3409
kthread+0x2c1/0x3a0 kernel/kthread.c:389
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:144
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
Tested on:
commit: d35b2284 Add linux-next specific files for 20240607
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=163368a1980000
kernel config: https://syzkaller.appspot.com/x/.config?x=39f353a8458f74bb
dashboard link: https://syzkaller.appspot.com/bug?extid=edd9fe0d3a65b14588d5
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=14750a19980000
