* [syzbot] [usb?] possible deadlock in fifo_open (2)
@ 2026-08-29 19:42 syzbot
0 siblings, 0 replies; only message in thread
From: syzbot @ 2026-08-29 19:42 UTC (permalink / raw)
To: gregkh, linux-kernel, linux-usb, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: 818bebeb63dd drm/xe: Don't hand out the flat CCS storage a..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1140199e580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ccca94d2c01b9e78
dashboard link: https://syzkaller.appspot.com/bug?extid=e6737343c72c2accf79e
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-818bebeb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6e4100526b12/vmlinux-818bebeb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/723c4783ee96/bzImage-818bebeb.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e6737343c72c2accf79e@syzkaller.appspotmail.com
9p: Bad value for 'version'
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G L
------------------------------------------------------
syz.8.3362/18795 is trying to acquire lock:
ffff88805662e860 (&pipe->mutex){+.+.}-{4:4}, at: fifo_open+0x139/0xb40 fs/pipe.c:1235
but task is already holding lock:
ffff88802b41f920 (&common->filesem){++++}-{4:4}, at: fsg_store_file+0x193/0x450 drivers/usb/gadget/function/storage_common.c:452
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #5 (&common->filesem){++++}-{4:4}:
lock_acquire kernel/locking/lockdep.c:5886 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
down_read+0x99/0x4c0 kernel/locking/rwsem.c:1574
fsg_store_cdrom+0xe2/0x190 drivers/usb/gadget/function/storage_common.c:478
flush_write_buffer fs/configfs/file.c:207 [inline]
configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6af/0x1050 fs/read_write.c:687
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #4 (&p->frag_sem){++++}-{4:4}:
lock_acquire kernel/locking/lockdep.c:5886 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
down_read+0x99/0x4c0 kernel/locking/rwsem.c:1574
flush_write_buffer fs/configfs/file.c:205 [inline]
configfs_write_iter+0x218/0x4e0 fs/configfs/file.c:229
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6af/0x1050 fs/read_write.c:687
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #3 (&buffer->mutex#2){+.+.}-{4:4}:
lock_acquire kernel/locking/lockdep.c:5886 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x1a4/0x1bc0 kernel/locking/mutex.c:821
configfs_read_iter+0x79/0x6f0 fs/configfs/file.c:86
__kernel_read+0x397/0xad0 fs/read_write.c:532
integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28
ima_calc_file_hash_tfm+0x25e/0x350 security/integrity/ima/ima_crypto.c:222
ima_calc_file_hash+0x1e3/0x380 security/integrity/ima/ima_crypto.c:280
ima_collect_measurement+0x94f/0xb30 security/integrity/ima/ima_api.c:300
process_measurement+0xdfe/0x2350 security/integrity/ima/ima_main.c:425
ima_file_check+0xc3/0x110 security/integrity/ima/ima_main.c:685
security_file_post_open+0xc4/0x210 security/security.c:2755
do_open fs/namei.c:4839 [inline]
path_openat+0x5cd/0x2440 fs/namei.c:5000
do_file_open+0x20e/0x430 fs/namei.c:5029
do_sys_openat2+0x10f/0x1e0 fs/open.c:1417
do_sys_open fs/open.c:1423 [inline]
__do_sys_openat fs/open.c:1439 [inline]
__se_sys_openat fs/open.c:1434 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1434
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #2 (&ima_iint_mutex_key[depth]){+.+.}-{4:4}:
lock_acquire kernel/locking/lockdep.c:5886 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x1a4/0x1bc0 kernel/locking/mutex.c:821
process_measurement+0x5ab/0x2350 security/integrity/ima/ima_main.c:319
ima_file_check+0xc3/0x110 security/integrity/ima/ima_main.c:685
security_file_post_open+0xc4/0x210 security/security.c:2755
do_open fs/namei.c:4839 [inline]
path_openat+0x5cd/0x2440 fs/namei.c:5000
do_file_open+0x20e/0x430 fs/namei.c:5029
file_open_name+0x1c3/0x3e0 fs/open.c:1375
filp_open+0x2e/0x50 fs/open.c:1392
kernel_read_file_from_path_initns+0xec/0x240 fs/kernel_read_file.c:159
fw_get_filesystem_firmware drivers/base/firmware_loader/main.c:549 [inline]
_request_firmware+0x733/0x13c0 drivers/base/firmware_loader/main.c:873
request_firmware+0x35/0x50 drivers/base/firmware_loader/main.c:948
reg_reload_regdb+0x85/0x460 net/wireless/reg.c:1067
genl_family_rcv_msg_doit+0x214/0x300 net/netlink/genetlink.c:1114
genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
genl_rcv_msg+0x560/0x800 net/netlink/genetlink.c:1209
netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2556
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1900
sock_sendmsg_nosec net/socket.c:800 [inline]
__sock_sendmsg net/socket.c:815 [inline]
____sys_sendmsg+0xa4d/0xbe0 net/socket.c:2713
___sys_sendmsg+0x190/0x1e0 net/socket.c:2767
__sys_sendmsg+0x160/0x210 net/socket.c:2799
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (cb_lock){++++}-{4:4}:
lock_acquire kernel/locking/lockdep.c:5886 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
down_read+0x99/0x4c0 kernel/locking/rwsem.c:1574
genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1900
sock_sendmsg_nosec net/socket.c:800 [inline]
__sock_sendmsg net/socket.c:815 [inline]
sock_sendmsg+0x394/0x410 net/socket.c:838
splice_to_socket+0xb3c/0x11a0 fs/splice.c:884
do_splice_from fs/splice.c:936 [inline]
do_splice+0x109c/0x1fa0 fs/splice.c:1349
__do_splice+0x33b/0x370 fs/splice.c:1431
__do_sys_splice fs/splice.c:1634 [inline]
__se_sys_splice fs/splice.c:1616 [inline]
__x64_sys_splice+0x187/0x250 fs/splice.c:1616
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&pipe->mutex){+.+.}-{4:4}:
check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3181
check_prevs_add kernel/locking/lockdep.c:3300 [inline]
validate_chain kernel/locking/lockdep.c:3924 [inline]
__lock_acquire+0x1492/0x1ec0 kernel/locking/lockdep.c:5253
lock_acquire kernel/locking/lockdep.c:5886 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x1a4/0x1bc0 kernel/locking/mutex.c:821
fifo_open+0x139/0xb40 fs/pipe.c:1235
do_dentry_open+0x6ab/0x14d0 fs/open.c:996
vfs_open+0x82/0x3f0 fs/open.c:1101
do_open fs/namei.c:4837 [inline]
path_openat+0x19fa/0x2440 fs/namei.c:5000
do_file_open+0x20e/0x430 fs/namei.c:5029
file_open_name+0x1c3/0x3e0 fs/open.c:1375
filp_open+0x2e/0x50 fs/open.c:1392
fsg_lun_open+0x9e/0x7b0 drivers/usb/gadget/function/storage_common.c:199
fsg_store_file+0x1e7/0x450 drivers/usb/gadget/function/storage_common.c:455
flush_write_buffer fs/configfs/file.c:207 [inline]
configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6af/0x1050 fs/read_write.c:687
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
&pipe->mutex --> &p->frag_sem --> &common->filesem
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&common->filesem);
lock(&p->frag_sem);
lock(&common->filesem);
lock(&pipe->mutex);
*** DEADLOCK ***
locks held by syz.8.3362/18795: 5, last CPU#0:
#0: ffff888034a2c9b0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff8880238a2460 (sb_writers#18){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffff88803d2cde80 (&buffer->mutex#2){+.+.}-{4:4}, at: configfs_write_iter+0x76/0x4e0 fs/configfs/file.c:226
#3: ffff88803c8bd070 (&p->frag_sem){++++}-{4:4}, at: flush_write_buffer fs/configfs/file.c:205 [inline]
#3: ffff88803c8bd070 (&p->frag_sem){++++}-{4:4}, at: configfs_write_iter+0x218/0x4e0 fs/configfs/file.c:229
#4: ffff88802b41f920 (&common->filesem){++++}-{4:4}, at: fsg_store_file+0x193/0x450 drivers/usb/gadget/function/storage_common.c:452
stack backtrace:
CPU: 0 UID: 0 PID: 18795 Comm: syz.8.3362 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_circular_bug.cold+0x178/0x1be kernel/locking/lockdep.c:2059
check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2191
check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3181
check_prevs_add kernel/locking/lockdep.c:3300 [inline]
validate_chain kernel/locking/lockdep.c:3924 [inline]
__lock_acquire+0x1492/0x1ec0 kernel/locking/lockdep.c:5253
lock_acquire kernel/locking/lockdep.c:5886 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x1a4/0x1bc0 kernel/locking/mutex.c:821
fifo_open+0x139/0xb40 fs/pipe.c:1235
do_dentry_open+0x6ab/0x14d0 fs/open.c:996
vfs_open+0x82/0x3f0 fs/open.c:1101
do_open fs/namei.c:4837 [inline]
path_openat+0x19fa/0x2440 fs/namei.c:5000
do_file_open+0x20e/0x430 fs/namei.c:5029
file_open_name+0x1c3/0x3e0 fs/open.c:1375
filp_open+0x2e/0x50 fs/open.c:1392
fsg_lun_open+0x9e/0x7b0 drivers/usb/gadget/function/storage_common.c:199
fsg_store_file+0x1e7/0x450 drivers/usb/gadget/function/storage_common.c:455
flush_write_buffer fs/configfs/file.c:207 [inline]
configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6af/0x1050 fs/read_write.c:687
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f485679e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4857660028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f4856a25fa0 RCX: 00007f485679e0d9
RDX: 0000000000000005 RSI: 00002000000003c0 RDI: 0000000000000003
RBP: 00007f4856835024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4856a26038 R14: 00007f4856a25fa0 R15: 00007ffd7288fbb8
</TASK>
mass_storage.0/lun.0: unable to open backing file: file0
---
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#syz undup
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2026-08-29 19:42 [syzbot] [usb?] possible deadlock in fifo_open (2) syzbot
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