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a91c809659
The original code causes a circular locking dependency found by lockdep.
======================================================
WARNING: possible circular locking dependency detected
6.16.0-rc6-lgci-xe-xe-pw-151626v3+ #1 Tainted: G S U
------------------------------------------------------
xe_fault_inject/5091 is trying to acquire lock:
ffff888156815688 ((work_completion)(&(&devcd->del_wk)->work)){+.+.}-{0:0}, at: __flush_work+0x25d/0x660
but task is already holding lock:
ffff888156815620 (&devcd->mutex){+.+.}-{3:3}, at: dev_coredump_put+0x3f/0xa0
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&devcd->mutex){+.+.}-{3:3}:
mutex_lock_nested+0x4e/0xc0
devcd_data_write+0x27/0x90
sysfs_kf_bin_write+0x80/0xf0
kernfs_fop_write_iter+0x169/0x220
vfs_write+0x293/0x560
ksys_write+0x72/0xf0
__x64_sys_write+0x19/0x30
x64_sys_call+0x2bf/0x2660
do_syscall_64+0x93/0xb60
entry_SYSCALL_64_after_hwframe+0x76/0x7e
-> #1 (kn->active#236){++++}-{0:0}:
kernfs_drain+0x1e2/0x200
__kernfs_remove+0xae/0x400
kernfs_remove_by_name_ns+0x5d/0xc0
remove_files+0x54/0x70
sysfs_remove_group+0x3d/0xa0
sysfs_remove_groups+0x2e/0x60
device_remove_attrs+0xc7/0x100
device_del+0x15d/0x3b0
devcd_del+0x19/0x30
process_one_work+0x22b/0x6f0
worker_thread+0x1e8/0x3d0
kthread+0x11c/0x250
ret_from_fork+0x26c/0x2e0
ret_from_fork_asm+0x1a/0x30
-> #0 ((work_completion)(&(&devcd->del_wk)->work)){+.+.}-{0:0}:
__lock_acquire+0x1661/0x2860
lock_acquire+0xc4/0x2f0
__flush_work+0x27a/0x660
flush_delayed_work+0x5d/0xa0
dev_coredump_put+0x63/0xa0
xe_driver_devcoredump_fini+0x12/0x20 [xe]
devm_action_release+0x12/0x30
release_nodes+0x3a/0x120
devres_release_all+0x8a/0xd0
device_unbind_cleanup+0x12/0x80
device_release_driver_internal+0x23a/0x280
device_driver_detach+0x14/0x20
unbind_store+0xaf/0xc0
drv_attr_store+0x21/0x50
sysfs_kf_write+0x4a/0x80
kernfs_fop_write_iter+0x169/0x220
vfs_write+0x293/0x560
ksys_write+0x72/0xf0
__x64_sys_write+0x19/0x30
x64_sys_call+0x2bf/0x2660
do_syscall_64+0x93/0xb60
entry_SYSCALL_64_after_hwframe+0x76/0x7e
other info that might help us debug this:
Chain exists of: (work_completion)(&(&devcd->del_wk)->work) --> kn->active#236 --> &devcd->mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&devcd->mutex);
lock(kn->active#236);
lock(&devcd->mutex);
lock((work_completion)(&(&devcd->del_wk)->work));
*** DEADLOCK ***
5 locks held by xe_fault_inject/5091:
#0: ffff8881129f9488 (sb_writers#5){.+.+}-{0:0}, at: ksys_write+0x72/0xf0
#1: ffff88810c755078 (&of->mutex#2){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x123/0x220
#2: ffff8881054811a0 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0x55/0x280
#3: ffff888156815620 (&devcd->mutex){+.+.}-{3:3}, at: dev_coredump_put+0x3f/0xa0
#4: ffffffff8359e020 (rcu_read_lock){....}-{1:2}, at: __flush_work+0x72/0x660
stack backtrace:
CPU: 14 UID: 0 PID: 5091 Comm: xe_fault_inject Tainted: G S U 6.16.0-rc6-lgci-xe-xe-pw-151626v3+ #1 PREEMPT_{RT,(lazy)}
Tainted: [S]=CPU_OUT_OF_SPEC, [U]=USER
Hardware name: Micro-Star International Co., Ltd. MS-7D25/PRO Z690-A DDR4(MS-7D25), BIOS 1.10 12/13/2021
Call Trace:
<TASK>
dump_stack_lvl+0x91/0xf0
dump_stack+0x10/0x20
print_circular_bug+0x285/0x360
check_noncircular+0x135/0x150
? register_lock_class+0x48/0x4a0
__lock_acquire+0x1661/0x2860
lock_acquire+0xc4/0x2f0
? __flush_work+0x25d/0x660
? mark_held_locks+0x46/0x90
? __flush_work+0x25d/0x660
__flush_work+0x27a/0x660
? __flush_work+0x25d/0x660
? trace_hardirqs_on+0x1e/0xd0
? __pfx_wq_barrier_func+0x10/0x10
flush_delayed_work+0x5d/0xa0
dev_coredump_put+0x63/0xa0
xe_driver_devcoredump_fini+0x12/0x20 [xe]
devm_action_release+0x12/0x30
release_nodes+0x3a/0x120
devres_release_all+0x8a/0xd0
device_unbind_cleanup+0x12/0x80
device_release_driver_internal+0x23a/0x280
? bus_find_device+0xa8/0xe0
device_driver_detach+0x14/0x20
unbind_store+0xaf/0xc0
drv_attr_store+0x21/0x50
sysfs_kf_write+0x4a/0x80
kernfs_fop_write_iter+0x169/0x220
vfs_write+0x293/0x560
ksys_write+0x72/0xf0
__x64_sys_write+0x19/0x30
x64_sys_call+0x2bf/0x2660
do_syscall_64+0x93/0xb60
? __f_unlock_pos+0x15/0x20
? __x64_sys_getdents64+0x9b/0x130
? __pfx_filldir64+0x10/0x10
? do_syscall_64+0x1a2/0xb60
? clear_bhb_loop+0x30/0x80
? clear_bhb_loop+0x30/0x80
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x76e292edd574
Code: c7 00 16 00 00 00 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 80 3d d5 ea 0e 00 00 74 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 55 48 89 e5 48 83 ec 20 48 89
RSP: 002b:00007fffe247a828 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000076e292edd574
RDX: 000000000000000c RSI: 00006267f6306063 RDI: 000000000000000b
RBP: 000000000000000c R08: 000076e292fc4b20 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00006267f6306063
R13: 000000000000000b R14: 00006267e6859c00 R15: 000076e29322a000
</TASK>
xe 0000:03:00.0: [drm] Xe device coredump has been deleted.
Fixes: 01daccf748 ("devcoredump : Serialize devcd_del work")
Cc: Mukesh Ojha <quic_mojha@quicinc.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org # v6.1+
Signed-off-by: Maarten Lankhorst <dev@lankhorst.se>
Cc: Matthew Brost <matthew.brost@intel.com>
Acked-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250723142416.1020423-1-dev@lankhorst.se
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
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