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* [syzbot] [kernfs?] possible deadlock in walk_component (4)
@ 2024-08-18 22:16 syzbot
  2025-02-02 18:56 ` syzbot
  0 siblings, 1 reply; 4+ messages in thread
From: syzbot @ 2024-08-18 22:16 UTC (permalink / raw)
  To: gregkh, linux-kernel, syzkaller-bugs, tj

Hello,

syzbot found the following issue on:

HEAD commit:    6b0f8db921ab Merge tag 'execve-v6.11-rc4' of git://git.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16766c05980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=54e9d4be0c7a0d11
dashboard link: https://syzkaller.appspot.com/bug?extid=b4567a8b2d2ad5f9dd06
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-6b0f8db9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5829b92d3000/vmlinux-6b0f8db9.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0b382f2bc118/bzImage-6b0f8db9.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b4567a8b2d2ad5f9dd06@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.11.0-rc3-syzkaller-00013-g6b0f8db921ab #0 Not tainted
------------------------------------------------------
syz.0.2542/15091 is trying to acquire lock:
ffff888047e58cf8 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:809 [inline]
ffff888047e58cf8 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}, at: lookup_slow fs/namei.c:1734 [inline]
ffff888047e58cf8 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}, at: walk_component+0x342/0x5b0 fs/namei.c:2039

but task is already holding lock:
ffff8880484c6488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x281/0x500 fs/kernfs/file.c:325

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&of->mutex){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
       kernfs_fop_write_iter+0x281/0x500 fs/kernfs/file.c:325
       iter_file_splice_write+0x906/0x10b0 fs/splice.c:743
       do_splice_from fs/splice.c:941 [inline]
       do_splice+0x148c/0x1f90 fs/splice.c:1354
       __do_splice+0x327/0x360 fs/splice.c:1436
       __do_sys_splice fs/splice.c:1652 [inline]
       __se_sys_splice fs/splice.c:1634 [inline]
       __x64_sys_splice+0x1d2/0x260 fs/splice.c:1634
       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

-> #2 (&pipe->mutex){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
       pipe_lock fs/pipe.c:92 [inline]
       pipe_lock+0x64/0x80 fs/pipe.c:89
       iter_file_splice_write+0x1f0/0x10b0 fs/splice.c:687
       do_splice_from fs/splice.c:941 [inline]
       do_splice+0x148c/0x1f90 fs/splice.c:1354
       __do_splice+0x327/0x360 fs/splice.c:1436
       __do_sys_splice fs/splice.c:1652 [inline]
       __se_sys_splice fs/splice.c:1634 [inline]
       __x64_sys_splice+0x1d2/0x260 fs/splice.c:1634
       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

-> #1 (sb_writers#6){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1675 [inline]
       sb_start_write include/linux/fs.h:1811 [inline]
       mnt_want_write+0x6f/0x450 fs/namespace.c:515
       ovl_create_object+0x12e/0x300 fs/overlayfs/dir.c:642
       lookup_open.isra.0+0x10a1/0x13c0 fs/namei.c:3578
       open_last_lookups fs/namei.c:3647 [inline]
       path_openat+0xa3b/0x2d20 fs/namei.c:3883
       do_filp_open+0x1dc/0x430 fs/namei.c:3913
       do_sys_openat2+0x17a/0x1e0 fs/open.c:1416
       do_sys_open fs/open.c:1431 [inline]
       __do_sys_openat fs/open.c:1447 [inline]
       __se_sys_openat fs/open.c:1442 [inline]
       __x64_sys_openat+0x175/0x210 fs/open.c:1442
       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

-> #0 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3133 [inline]
       check_prevs_add kernel/locking/lockdep.c:3252 [inline]
       validate_chain kernel/locking/lockdep.c:3868 [inline]
       __lock_acquire+0x24ed/0x3cb0 kernel/locking/lockdep.c:5142
       lock_acquire kernel/locking/lockdep.c:5759 [inline]
       lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5724
       down_read+0x9a/0x330 kernel/locking/rwsem.c:1526
       inode_lock_shared include/linux/fs.h:809 [inline]
       lookup_slow fs/namei.c:1734 [inline]
       walk_component+0x342/0x5b0 fs/namei.c:2039
       lookup_last fs/namei.c:2542 [inline]
       path_lookupat+0x17f/0x770 fs/namei.c:2566
       filename_lookup+0x1e5/0x5b0 fs/namei.c:2595
       kern_path+0x35/0x50 fs/namei.c:2703
       lookup_bdev+0xd9/0x280 block/bdev.c:1157
       resume_store+0x1d8/0x460 kernel/power/hibernate.c:1235
       kobj_attr_store+0x55/0x80 lib/kobject.c:840
       sysfs_kf_write+0x117/0x170 fs/sysfs/file.c:136
       kernfs_fop_write_iter+0x343/0x500 fs/kernfs/file.c:334
       new_sync_write fs/read_write.c:497 [inline]
       vfs_write+0x6b6/0x1140 fs/read_write.c:590
       ksys_write+0x12f/0x260 fs/read_write.c:643
       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

other info that might help us debug this:

Chain exists of:
  &ovl_i_mutex_dir_key[depth] --> &pipe->mutex --> &of->mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&of->mutex);
                               lock(&pipe->mutex);
                               lock(&of->mutex);
  rlock(&ovl_i_mutex_dir_key[depth]);

 *** DEADLOCK ***

4 locks held by syz.0.2542/15091:
 #0: ffff8880298c19c8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xeb/0x180 fs/file.c:1187
 #1: ffff888024928420 (sb_writers#9){.+.+}-{0:0}, at: ksys_write+0x12f/0x260 fs/read_write.c:643
 #2: ffff8880484c6488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x281/0x500 fs/kernfs/file.c:325
 #3: ffff888016744698 (kn->active#77){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2a4/0x500 fs/kernfs/file.c:326

stack backtrace:
CPU: 1 UID: 0 PID: 15091 Comm: syz.0.2542 Not tainted 6.11.0-rc3-syzkaller-00013-g6b0f8db921ab #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:119
 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2186
 check_prev_add kernel/locking/lockdep.c:3133 [inline]
 check_prevs_add kernel/locking/lockdep.c:3252 [inline]
 validate_chain kernel/locking/lockdep.c:3868 [inline]
 __lock_acquire+0x24ed/0x3cb0 kernel/locking/lockdep.c:5142
 lock_acquire kernel/locking/lockdep.c:5759 [inline]
 lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5724
 down_read+0x9a/0x330 kernel/locking/rwsem.c:1526
 inode_lock_shared include/linux/fs.h:809 [inline]
 lookup_slow fs/namei.c:1734 [inline]
 walk_component+0x342/0x5b0 fs/namei.c:2039
 lookup_last fs/namei.c:2542 [inline]
 path_lookupat+0x17f/0x770 fs/namei.c:2566
 filename_lookup+0x1e5/0x5b0 fs/namei.c:2595
 kern_path+0x35/0x50 fs/namei.c:2703
 lookup_bdev+0xd9/0x280 block/bdev.c:1157
 resume_store+0x1d8/0x460 kernel/power/hibernate.c:1235
 kobj_attr_store+0x55/0x80 lib/kobject.c:840
 sysfs_kf_write+0x117/0x170 fs/sysfs/file.c:136
 kernfs_fop_write_iter+0x343/0x500 fs/kernfs/file.c:334
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0x6b6/0x1140 fs/read_write.c:590
 ksys_write+0x12f/0x260 fs/read_write.c:643
 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: 0033:0x7efcd1f799f9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007efcd2d56038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007efcd2115f80 RCX: 00007efcd1f799f9
RDX: 0000000000000012 RSI: 0000000020000140 RDI: 0000000000000009
RBP: 00007efcd1fe78ee R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007efcd2115f80 R15: 00007ffdbb59c4e8
 </TASK>
PM: Image not found (code -6)


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

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

If you want to overwrite report's subsystems, reply with:
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(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [syzbot] [kernfs?] possible deadlock in walk_component (4)
  2024-08-18 22:16 [syzbot] [kernfs?] possible deadlock in walk_component (4) syzbot
@ 2025-02-02 18:56 ` syzbot
  2025-02-03  8:39   ` Hillf Danton
  0 siblings, 1 reply; 4+ messages in thread
From: syzbot @ 2025-02-02 18:56 UTC (permalink / raw)
  To: gregkh, linux-kernel, syzkaller-bugs, tj

syzbot has found a reproducer for the following issue on:

HEAD commit:    69e858e0b8b2 Merge tag 'uml-for-linus-6.14-rc1' of git://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10dc6d18580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=98d83cc1742b7377
dashboard link: https://syzkaller.appspot.com/bug?extid=b4567a8b2d2ad5f9dd06
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=116fceb0580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15bf03df980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3d07b0558b0e/disk-69e858e0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e5e2250eb3b1/vmlinux-69e858e0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3e676d17effc/bzImage-69e858e0.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b4567a8b2d2ad5f9dd06@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.13.0-syzkaller-09760-g69e858e0b8b2 #0 Not tainted
------------------------------------------------------
syz-executor466/5830 is trying to acquire lock:
ffff88807997f398 (&type->i_mutex_dir_key#6){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:875 [inline]
ffff88807997f398 (&type->i_mutex_dir_key#6){++++}-{4:4}, at: lookup_slow fs/namei.c:1809 [inline]
ffff88807997f398 (&type->i_mutex_dir_key#6){++++}-{4:4}, at: walk_component+0x342/0x5b0 fs/namei.c:2114

but task is already holding lock:
ffffffff8e07d228 (param_lock){+.+.}-{4:4}, at: kernel_param_lock kernel/params.c:607 [inline]
ffffffff8e07d228 (param_lock){+.+.}-{4:4}, at: param_attr_store+0xe6/0x300 kernel/params.c:586

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (param_lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19b/0xb10 kernel/locking/mutex.c:730
       ieee80211_rate_control_ops_get net/mac80211/rate.c:220 [inline]
       rate_control_alloc net/mac80211/rate.c:266 [inline]
       ieee80211_init_rate_ctrl_alg+0x18d/0x6b0 net/mac80211/rate.c:1015
       ieee80211_register_hw+0x2077/0x3ff0 net/mac80211/main.c:1531
       mac80211_hwsim_new_radio+0x2c47/0x56d0 drivers/net/wireless/virtual/mac80211_hwsim.c:5558
       init_mac80211_hwsim+0x432/0x8c0 drivers/net/wireless/virtual/mac80211_hwsim.c:6910
       do_one_initcall+0x128/0x630 init/main.c:1257
       do_initcall_level init/main.c:1319 [inline]
       do_initcalls init/main.c:1335 [inline]
       do_basic_setup init/main.c:1354 [inline]
       kernel_init_freeable+0x58f/0x8b0 init/main.c:1568
       kernel_init+0x1c/0x2b0 init/main.c:1457
       ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #2 (rtnl_mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19b/0xb10 kernel/locking/mutex.c:730
       cgrp_css_online+0xa9/0x200 net/core/netprio_cgroup.c:157
       online_css+0xaf/0x350 kernel/cgroup/cgroup.c:5568
       css_create kernel/cgroup/cgroup.c:5652 [inline]
       cgroup_apply_control_enable+0x6d7/0xc80 kernel/cgroup/cgroup.c:3239
       cgroup_mkdir+0x398/0x1150 kernel/cgroup/cgroup.c:5847
       kernfs_iop_mkdir+0x14a/0x1d0 fs/kernfs/dir.c:1247
       vfs_mkdir+0x57d/0x860 fs/namei.c:4313
       do_mkdirat+0x301/0x3a0 fs/namei.c:4336
       __do_sys_mkdir fs/namei.c:4356 [inline]
       __se_sys_mkdir fs/namei.c:4354 [inline]
       __x64_sys_mkdir+0xef/0x140 fs/namei.c:4354
       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

-> #1 (cgroup_mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19b/0xb10 kernel/locking/mutex.c:730
       cgroup_lock include/linux/cgroup.h:368 [inline]
       cgroup_kn_lock_live+0x139/0x570 kernel/cgroup/cgroup.c:1662
       cgroup_rmdir+0x22/0x2d0 kernel/cgroup/cgroup.c:6045
       kernfs_iop_rmdir+0x143/0x1c0 fs/kernfs/dir.c:1265
       vfs_rmdir fs/namei.c:4396 [inline]
       vfs_rmdir+0x203/0x690 fs/namei.c:4373
       do_rmdir+0x3a2/0x410 fs/namei.c:4455
       __do_sys_rmdir fs/namei.c:4474 [inline]
       __se_sys_rmdir fs/namei.c:4472 [inline]
       __x64_sys_rmdir+0xc5/0x110 fs/namei.c:4472
       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

-> #0 (&type->i_mutex_dir_key#6){++++}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3163 [inline]
       check_prevs_add kernel/locking/lockdep.c:3282 [inline]
       validate_chain kernel/locking/lockdep.c:3906 [inline]
       __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5228
       lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5851
       down_read+0x9a/0x330 kernel/locking/rwsem.c:1524
       inode_lock_shared include/linux/fs.h:875 [inline]
       lookup_slow fs/namei.c:1809 [inline]
       walk_component+0x342/0x5b0 fs/namei.c:2114
       lookup_last fs/namei.c:2612 [inline]
       path_lookupat+0x17f/0x770 fs/namei.c:2636
       filename_lookup+0x221/0x5f0 fs/namei.c:2665
       kern_path+0x35/0x50 fs/namei.c:2773
       lookup_bdev+0xd9/0x280 block/bdev.c:1163
       bdev_file_open_by_path+0x83/0x330 block/bdev.c:1036
       add_device drivers/mtd/devices/block2mtd.c:279 [inline]
       block2mtd_setup2+0x32e/0xe30 drivers/mtd/devices/block2mtd.c:459
       block2mtd_setup+0x55/0x70 drivers/mtd/devices/block2mtd.c:476
       param_attr_store+0x18f/0x300 kernel/params.c:588
       module_attr_store+0x55/0x80 kernel/params.c:924
       sysfs_kf_write+0x117/0x170 fs/sysfs/file.c:139
       kernfs_fop_write_iter+0x33d/0x500 fs/kernfs/file.c:334
       new_sync_write fs/read_write.c:586 [inline]
       vfs_write+0x5ae/0x1150 fs/read_write.c:679
       ksys_write+0x12b/0x250 fs/read_write.c:731
       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

other info that might help us debug this:

Chain exists of:
  &type->i_mutex_dir_key#6 --> rtnl_mutex --> param_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(param_lock);
                               lock(rtnl_mutex);
                               lock(param_lock);
  rlock(&type->i_mutex_dir_key#6);

 *** DEADLOCK ***

4 locks held by syz-executor466/5830:
 #0: ffff8880244b2420 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12b/0x250 fs/read_write.c:731
 #1: ffff88802975f488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x27b/0x500 fs/kernfs/file.c:325
 #2: ffff88814c9e6008 (kn->active#4){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x29e/0x500 fs/kernfs/file.c:326
 #3: ffffffff8e07d228 (param_lock){+.+.}-{4:4}, at: kernel_param_lock kernel/params.c:607 [inline]
 #3: ffffffff8e07d228 (param_lock){+.+.}-{4:4}, at: param_attr_store+0xe6/0x300 kernel/params.c:586

stack backtrace:
CPU: 0 UID: 0 PID: 5830 Comm: syz-executor466 Not tainted 6.13.0-syzkaller-09760-g69e858e0b8b2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_circular_bug+0x490/0x760 kernel/locking/lockdep.c:2076
 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2208
 check_prev_add kernel/locking/lockdep.c:3163 [inline]
 check_prevs_add kernel/locking/lockdep.c:3282 [inline]
 validate_chain kernel/locking/lockdep.c:3906 [inline]
 __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5228
 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5851
 down_read+0x9a/0x330 kernel/locking/rwsem.c:1524
 inode_lock_shared include/linux/fs.h:875 [inline]
 lookup_slow fs/namei.c:1809 [inline]
 walk_component+0x342/0x5b0 fs/namei.c:2114
 lookup_last fs/namei.c:2612 [inline]
 path_lookupat+0x17f/0x770 fs/namei.c:2636
 filename_lookup+0x221/0x5f0 fs/namei.c:2665
 kern_path+0x35/0x50 fs/namei.c:2773
 lookup_bdev+0xd9/0x280 block/bdev.c:1163
 bdev_file_open_by_path+0x83/0x330 block/bdev.c:1036
 add_device drivers/mtd/devices/block2mtd.c:279 [inline]
 block2mtd_setup2+0x32e/0xe30 drivers/mtd/devices/block2mtd.c:459
 block2mtd_setup+0x55/0x70 drivers/mtd/devices/block2mtd.c:476
 param_attr_store+0x18f/0x300 kernel/params.c:588
 module_attr_store+0x55/0x80 kernel/params.c:924
 sysfs_kf_write+0x117/0x170 fs/sysfs/file.c:139
 kernfs_fop_write_iter+0x33d/0x500 fs/kernfs/file.c:334
 new_sync_write fs/read_write.c:586 [inline]
 vfs_write+0x5ae/0x1150 fs/read_write.c:679
 ksys_write+0x12b/0x250 fs/read_write.c:731
 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: 0033:0x7f64e4ab2ea9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 18 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffc0a6c6d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f64e4ab2ea9
RDX: 0000000000000003 RSI: 0000000020000000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f64e4afc036
R13: 00007fffc0a6c710 R14: 00007fffc0a6c750 R15: 0000000000000000
 </TASK>
block2mtd: error: cannot open device 3QI


---
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.

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [syzbot] [kernfs?] possible deadlock in walk_component (4)
  2025-02-02 18:56 ` syzbot
@ 2025-02-03  8:39   ` Hillf Danton
  2025-02-03  9:03     ` syzbot
  0 siblings, 1 reply; 4+ messages in thread
From: Hillf Danton @ 2025-02-03  8:39 UTC (permalink / raw)
  To: syzbot; +Cc: linux-kernel, syzkaller-bugs

On Sun, 02 Feb 2025 10:56:26 -0800
> syzbot has found a reproducer for the following issue on:
> 
> hEAD commit:    69e858e0b8b2 Merge tag 'uml-for-linus-6.14-rc1' of git://g..
> git tree:       upstream
> c reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15bf03df980000

#syz test

--- x/net/mac80211/rate.c
+++ y/net/mac80211/rate.c
@@ -217,7 +217,6 @@ ieee80211_rate_control_ops_get(const cha
 	const struct rate_control_ops *ops;
 	const char *alg_name;
 
-	kernel_param_lock(THIS_MODULE);
 	if (!name)
 		alg_name = ieee80211_default_rc_algo;
 	else
@@ -233,8 +232,6 @@ ieee80211_rate_control_ops_get(const cha
 		/* try built-in one if specific alg requested but not found */
 		ops = ieee80211_try_rate_control_ops_get(CONFIG_MAC80211_RC_DEFAULT);
 
-	kernel_param_unlock(THIS_MODULE);
-
 	return ops;
 }
 
--

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [syzbot] [kernfs?] possible deadlock in walk_component (4)
  2025-02-03  8:39   ` Hillf Danton
@ 2025-02-03  9:03     ` syzbot
  0 siblings, 0 replies; 4+ messages in thread
From: syzbot @ 2025-02-03  9:03 UTC (permalink / raw)
  To: hdanton, linux-kernel, syzkaller-bugs

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+b4567a8b2d2ad5f9dd06@syzkaller.appspotmail.com
Tested-by: syzbot+b4567a8b2d2ad5f9dd06@syzkaller.appspotmail.com

Tested on:

commit:         2014c95a Linux 6.14-rc1
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=148e5724580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ec9aa034f6454c35
dashboard link: https://syzkaller.appspot.com/bug?extid=b4567a8b2d2ad5f9dd06
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=162ded18580000

Note: testing is done by a robot and is best-effort only.

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2025-02-03  9:03 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2024-08-18 22:16 [syzbot] [kernfs?] possible deadlock in walk_component (4) syzbot
2025-02-02 18:56 ` syzbot
2025-02-03  8:39   ` Hillf Danton
2025-02-03  9:03     ` syzbot

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