* [syzbot] [bcachefs?] possible deadlock in pcpu_alloc_noprof
@ 2024-09-29 16:17 syzbot
2025-02-12 4:31 ` syzbot
2025-05-29 9:09 ` syzbot
0 siblings, 2 replies; 7+ messages in thread
From: syzbot @ 2024-09-29 16:17 UTC (permalink / raw)
To: kent.overstreet, linux-bcachefs, linux-kernel, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: 684a64bf32b6 Merge tag 'nfs-for-6.12-1' of git://git.linux..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14c6a99f980000
kernel config: https://syzkaller.appspot.com/x/.config?x=bd75e1a00004094f
dashboard link: https://syzkaller.appspot.com/bug?extid=fe63f377148a6371a9db
compiler: Debian clang version 15.0.6, 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-684a64bf.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f05b4b08a420/vmlinux-684a64bf.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d59f9edaf3bc/bzImage-684a64bf.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fe63f377148a6371a9db@syzkaller.appspotmail.com
netlink: 'syz.0.0': attribute type 1 has an invalid length.
netlink: 9364 bytes leftover after parsing attributes in process `syz.0.0'.
netlink: 'syz.0.0': attribute type 1 has an invalid length.
loop0: detected capacity change from 0 to 32768
bcachefs (loop0): starting version 1.7: mi_btree_bitmap opts=errors=continue,compression=lz4,no_splitbrain_check,norecovery,recovery_pass_last=check_dirents,reconstruct_alloc
bcachefs (loop0): recovering from clean shutdown, journal seq 7
bcachefs (loop0): Doing compatible version upgrade from 1.7: mi_btree_bitmap to 1.12: rebalance_work_acct_fix
running recovery passes: check_allocations
bcachefs (loop0): dropping and reconstructing all alloc info
bcachefs (loop0): accounting_read... done
bcachefs (loop0): alloc_read... done
bcachefs (loop0): stripes_read... done
bcachefs (loop0): snapshots_read... done
bcachefs (loop0): check_allocations...
btree ptr not marked in member info btree allocated bitmap
u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq 19bc58a6c09b6540 written 24 min_key POS_MIN durability: 1 ptr: 0:38:0 gen 0, fixing
btree ptr not marked in member info btree allocated bitmap
u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq c18f4a4face03c6 written 24 min_key POS_MIN durability: 1 ptr: 0:41:0 gen 0, fixing
btree ptr not marked in member info btree allocated bitmap
u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq 7675f41d391e5d36 written 16 min_key POS_MIN durability: 1 ptr: 0:35:0 gen 0, fixing
btree ptr not marked in member info btree allocated bitmap
u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq bcb9905dfb2993d5 written 16 min_key POS_MIN durability: 1 ptr: 0:32:0 gen 0, fixing
bucket 0:34 gen 0 data type user has wrong fragmentation_lru: got 0, should be 67108864, fixing
bucket 0:36 gen 0 data type user has wrong fragmentation_lru: got 0, should be 67108864, fixing
done
bcachefs (loop0): going read-write
bcachefs (loop0): Fixed errors, running fsck a second time to verify fs is clean
bcachefs (loop0): done starting filesystem
======================================================
WARNING: possible circular locking dependency detected
6.11.0-syzkaller-10547-g684a64bf32b6 #0 Not tainted
------------------------------------------------------
syz.0.0/5104 is trying to acquire lock:
ffffffff8ea171e8 (pcpu_alloc_mutex){+.+.}-{3:3}, at: pcpu_alloc_noprof+0x27f/0x16e0 mm/percpu.c:1795
but task is already holding lock:
ffff88804b901c50 (&bc->lock){+.+.}-{3:3}, at: bch2_btree_node_mem_alloc+0x4ec/0x1340 fs/bcachefs/btree_cache.c:782
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&bc->lock){+.+.}-{3:3}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
bch2_btree_cache_scan+0x192/0xd00 fs/bcachefs/btree_cache.c:460
do_shrink_slab+0x701/0x1160 mm/shrinker.c:435
shrink_slab+0x1093/0x14d0 mm/shrinker.c:662
shrink_one+0x43b/0x850 mm/vmscan.c:4818
shrink_many mm/vmscan.c:4879 [inline]
lru_gen_shrink_node mm/vmscan.c:4957 [inline]
shrink_node+0x3799/0x3de0 mm/vmscan.c:5937
kswapd_shrink_node mm/vmscan.c:6765 [inline]
balance_pgdat mm/vmscan.c:6957 [inline]
kswapd+0x1ca3/0x3700 mm/vmscan.c:7226
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
-> #1 (fs_reclaim){+.+.}-{0:0}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
__fs_reclaim_acquire mm/page_alloc.c:3834 [inline]
fs_reclaim_acquire+0x88/0x140 mm/page_alloc.c:3848
might_alloc include/linux/sched/mm.h:327 [inline]
slab_pre_alloc_hook mm/slub.c:4037 [inline]
slab_alloc_node mm/slub.c:4115 [inline]
__do_kmalloc_node mm/slub.c:4264 [inline]
__kmalloc_noprof+0xa9/0x400 mm/slub.c:4277
kmalloc_noprof include/linux/slab.h:882 [inline]
kzalloc_noprof include/linux/slab.h:1014 [inline]
pcpu_mem_zalloc mm/percpu.c:510 [inline]
pcpu_alloc_chunk mm/percpu.c:1443 [inline]
pcpu_create_chunk+0x57/0xbc0 mm/percpu-vm.c:338
pcpu_balance_populated mm/percpu.c:2075 [inline]
pcpu_balance_workfn+0xc4d/0xd40 mm/percpu.c:2212
process_one_work kernel/workqueue.c:3229 [inline]
process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310
worker_thread+0x870/0xd30 kernel/workqueue.c:3391
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
-> #0 (pcpu_alloc_mutex){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3158 [inline]
check_prevs_add kernel/locking/lockdep.c:3277 [inline]
validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
__lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5199
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
pcpu_alloc_noprof+0x27f/0x16e0 mm/percpu.c:1795
__six_lock_init+0x104/0x150 fs/bcachefs/six.c:863
bch2_btree_lock_init+0x38/0x100 fs/bcachefs/btree_locking.c:12
bch2_btree_node_mem_alloc+0x4f8/0x1340 fs/bcachefs/btree_cache.c:785
__bch2_btree_node_alloc fs/bcachefs/btree_update_interior.c:325 [inline]
bch2_btree_reserve_get+0x2df/0x1890 fs/bcachefs/btree_update_interior.c:554
bch2_btree_update_start+0xe56/0x14e0 fs/bcachefs/btree_update_interior.c:1252
bch2_btree_split_leaf+0x123/0x840 fs/bcachefs/btree_update_interior.c:1850
bch2_trans_commit_error+0x212/0x1390 fs/bcachefs/btree_trans_commit.c:903
__bch2_trans_commit+0x286e/0x9130 fs/bcachefs/btree_trans_commit.c:1135
bch2_trans_commit fs/bcachefs/btree_update.h:184 [inline]
bch2_logged_op_start+0x1c8/0x310 fs/bcachefs/logged_ops.c:83
bch2_truncate+0x1a5/0x2c0 fs/bcachefs/io_misc.c:291
bchfs_truncate+0x965/0xc70 fs/bcachefs/fs-io.c:464
notify_change+0xbca/0xe90 fs/attr.c:503
do_truncate+0x220/0x310 fs/open.c:65
handle_truncate fs/namei.c:3395 [inline]
do_open fs/namei.c:3778 [inline]
path_openat+0x2e1e/0x3590 fs/namei.c:3933
do_filp_open+0x235/0x490 fs/namei.c:3960
do_sys_openat2+0x13e/0x1d0 fs/open.c:1415
do_sys_open fs/open.c:1430 [inline]
__do_sys_openat fs/open.c:1446 [inline]
__se_sys_openat fs/open.c:1441 [inline]
__x64_sys_openat+0x247/0x2a0 fs/open.c:1441
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
pcpu_alloc_mutex --> fs_reclaim --> &bc->lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&bc->lock);
lock(fs_reclaim);
lock(&bc->lock);
lock(pcpu_alloc_mutex);
*** DEADLOCK ***
6 locks held by syz.0.0/5104:
#0: ffff88804e51c420 (sb_writers#11){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515
#1: ffff88804d1e9038 (&sb->s_type->i_mutex_key#19){++++}-{3:3}, at: inode_lock include/linux/fs.h:815 [inline]
#1: ffff88804d1e9038 (&sb->s_type->i_mutex_key#19){++++}-{3:3}, at: do_truncate+0x20c/0x310 fs/open.c:63
#2: ffff88804b900a38 (&c->snapshot_create_lock){.+.+}-{3:3}, at: bch2_truncate+0x16d/0x2c0 fs/bcachefs/io_misc.c:290
#3: ffff88804b904398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:151 [inline]
#3: ffff88804b904398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:250 [inline]
#3: ffff88804b904398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: __bch2_trans_get+0x7de/0xd20 fs/bcachefs/btree_iter.c:3215
#4: ffff88804b9266d0 (&c->gc_lock){++++}-{3:3}, at: bch2_btree_update_start+0x682/0x14e0 fs/bcachefs/btree_update_interior.c:1202
#5: ffff88804b901c50 (&bc->lock){+.+.}-{3:3}, at: bch2_btree_node_mem_alloc+0x4ec/0x1340 fs/bcachefs/btree_cache.c:782
stack backtrace:
CPU: 0 UID: 0 PID: 5104 Comm: syz.0.0 Not tainted 6.11.0-syzkaller-10547-g684a64bf32b6 #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:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2203
check_prev_add kernel/locking/lockdep.c:3158 [inline]
check_prevs_add kernel/locking/lockdep.c:3277 [inline]
validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
__lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5199
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
pcpu_alloc_noprof+0x27f/0x16e0 mm/percpu.c:1795
__six_lock_init+0x104/0x150 fs/bcachefs/six.c:863
bch2_btree_lock_init+0x38/0x100 fs/bcachefs/btree_locking.c:12
bch2_btree_node_mem_alloc+0x4f8/0x1340 fs/bcachefs/btree_cache.c:785
__bch2_btree_node_alloc fs/bcachefs/btree_update_interior.c:325 [inline]
bch2_btree_reserve_get+0x2df/0x1890 fs/bcachefs/btree_update_interior.c:554
bch2_btree_update_start+0xe56/0x14e0 fs/bcachefs/btree_update_interior.c:1252
bch2_btree_split_leaf+0x123/0x840 fs/bcachefs/btree_update_interior.c:1850
bch2_trans_commit_error+0x212/0x1390 fs/bcachefs/btree_trans_commit.c:903
__bch2_trans_commit+0x286e/0x9130 fs/bcachefs/btree_trans_commit.c:1135
bch2_trans_commit fs/bcachefs/btree_update.h:184 [inline]
bch2_logged_op_start+0x1c8/0x310 fs/bcachefs/logged_ops.c:83
bch2_truncate+0x1a5/0x2c0 fs/bcachefs/io_misc.c:291
bchfs_truncate+0x965/0xc70 fs/bcachefs/fs-io.c:464
notify_change+0xbca/0xe90 fs/attr.c:503
do_truncate+0x220/0x310 fs/open.c:65
handle_truncate fs/namei.c:3395 [inline]
do_open fs/namei.c:3778 [inline]
path_openat+0x2e1e/0x3590 fs/namei.c:3933
do_filp_open+0x235/0x490 fs/namei.c:3960
do_sys_openat2+0x13e/0x1d0 fs/open.c:1415
do_sys_open fs/open.c:1430 [inline]
__do_sys_openat fs/open.c:1446 [inline]
__se_sys_openat fs/open.c:1441 [inline]
__x64_sys_openat+0x247/0x2a0 fs/open.c:1441
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4a4bf7df39
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:00007f4a4cdf8038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f4a4c135f80 RCX: 00007f4a4bf7df39
RDX: 0000000000000300 RSI: 0000000020000300 RDI: ffffffffffffff9c
RBP: 00007f4a4bff0b76 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f4a4c135f80 R15: 00007fff8cf7cfa8
</TASK>
bucket 0:34 gen 0 data type user sector count overflow: 0 + -8 > U32_MAX
while marking u64s 7 type extent 536870913:8:U32_MAX len 8 ver 0: durability: 1 crc: c_size 8 size 8 offset 0 nonce 0 csum crc32c 0:cec3872e compress incompressible ptr: 0:34:0 gen 0, continuing
bucket 0:34 gen 0 data type user sector count overflow: 0 + -8 > U32_MAX
while marking u64s 7 type extent 536870913:8:U32_MAX len 8 ver 0: durability: 1 crc: c_size 8 size 8 offset 0 nonce 0 csum crc32c 0:cec3872e compress incompressible ptr: 0:34:0 gen 0, continuing
bucket 0:34 gen 0 data type user sector count overflow: 0 + -8 > U32_MAX
while marking u64s 7 type extent 536870913:8:U32_MAX len 8 ver 0: durability: 1 crc: c_size 8 size 8 offset 0 nonce 0 csum crc32c 0:cec3872e compress incompressible ptr: 0:34:0 gen 0, continuing
syz.0.0 (5104) used greatest stack depth: 6384 bytes left
---
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See https://goo.gl/tpsmEJ for more information about syzbot.
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syzbot will keep track of this issue. See:
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If the report is already addressed, let syzbot know by replying with:
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If you want to overwrite report's subsystems, reply with:
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If you want to undo deduplication, reply with:
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [syzbot] [bcachefs?] possible deadlock in pcpu_alloc_noprof
2024-09-29 16:17 [syzbot] [bcachefs?] possible deadlock in pcpu_alloc_noprof syzbot
@ 2025-02-12 4:31 ` syzbot
2025-02-12 9:22 ` Alan Huang
2025-02-24 18:52 ` Alan Huang
2025-05-29 9:09 ` syzbot
1 sibling, 2 replies; 7+ messages in thread
From: syzbot @ 2025-02-12 4:31 UTC (permalink / raw)
To: kent.overstreet, linux-bcachefs, linux-kernel, syzkaller-bugs
syzbot has found a reproducer for the following issue on:
HEAD commit: 09fbf3d50205 Merge tag 'tomoyo-pr-20250211' of git://git.c..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14370aa4580000
kernel config: https://syzkaller.appspot.com/x/.config?x=3c2347dd6174fbe2
dashboard link: https://syzkaller.appspot.com/bug?extid=fe63f377148a6371a9db
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=17404718580000
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-09fbf3d5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/835b3d29c46c/vmlinux-09fbf3d5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ff4bfd8a5d42/bzImage-09fbf3d5.xz
mounted in repro #1: https://storage.googleapis.com/syzbot-assets/24d046ee591e/mount_7.gz
mounted in repro #2: https://storage.googleapis.com/syzbot-assets/fc8a49472f19/mount_9.gz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fe63f377148a6371a9db@syzkaller.appspotmail.com
bcachefs (loop0): initializing new filesystem
bcachefs (loop0): going read-write
bcachefs (loop0): marking superblocks
======================================================
WARNING: possible circular locking dependency detected
6.14.0-rc2-syzkaller-00039-g09fbf3d50205 #0 Not tainted
------------------------------------------------------
syz.0.21/5625 is trying to acquire lock:
ffffffff8ea19608 (pcpu_alloc_mutex){+.+.}-{4:4}, at: pcpu_alloc_noprof+0x293/0x1760 mm/percpu.c:1782
but task is already holding lock:
ffff888051401c68 (&bc->lock){+.+.}-{4:4}, at: bch2_btree_node_mem_alloc+0x559/0x16f0 fs/bcachefs/btree_cache.c:804
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&bc->lock){+.+.}-{4:4}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
__mutex_lock_common kernel/locking/mutex.c:585 [inline]
__mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
bch2_btree_cache_scan+0x184/0xec0 fs/bcachefs/btree_cache.c:482
do_shrink_slab+0x72d/0x1160 mm/shrinker.c:437
shrink_slab+0x1093/0x14d0 mm/shrinker.c:664
shrink_one+0x43b/0x850 mm/vmscan.c:4868
shrink_many mm/vmscan.c:4929 [inline]
lru_gen_shrink_node mm/vmscan.c:5007 [inline]
shrink_node+0x37c5/0x3e50 mm/vmscan.c:5978
kswapd_shrink_node mm/vmscan.c:6807 [inline]
balance_pgdat mm/vmscan.c:6999 [inline]
kswapd+0x20f3/0x3b10 mm/vmscan.c:7264
kthread+0x7a9/0x920 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
-> #1 (fs_reclaim){+.+.}-{0:0}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
__fs_reclaim_acquire mm/page_alloc.c:3853 [inline]
fs_reclaim_acquire+0x88/0x130 mm/page_alloc.c:3867
might_alloc include/linux/sched/mm.h:318 [inline]
slab_pre_alloc_hook mm/slub.c:4066 [inline]
slab_alloc_node mm/slub.c:4144 [inline]
__do_kmalloc_node mm/slub.c:4293 [inline]
__kmalloc_noprof+0xae/0x4c0 mm/slub.c:4306
kmalloc_noprof include/linux/slab.h:905 [inline]
kzalloc_noprof include/linux/slab.h:1037 [inline]
pcpu_mem_zalloc mm/percpu.c:510 [inline]
pcpu_alloc_chunk mm/percpu.c:1430 [inline]
pcpu_create_chunk+0x57/0xbc0 mm/percpu-vm.c:338
pcpu_balance_populated mm/percpu.c:2063 [inline]
pcpu_balance_workfn+0xc4d/0xd40 mm/percpu.c:2200
process_one_work kernel/workqueue.c:3236 [inline]
process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317
worker_thread+0x870/0xd30 kernel/workqueue.c:3398
kthread+0x7a9/0x920 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
-> #0 (pcpu_alloc_mutex){+.+.}-{4:4}:
check_prev_add kernel/locking/lockdep.c:3163 [inline]
check_prevs_add kernel/locking/lockdep.c:3282 [inline]
validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
__lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
__mutex_lock_common kernel/locking/mutex.c:585 [inline]
__mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
pcpu_alloc_noprof+0x293/0x1760 mm/percpu.c:1782
__six_lock_init+0x104/0x150 fs/bcachefs/six.c:876
bch2_btree_lock_init+0x38/0x100 fs/bcachefs/btree_locking.c:12
bch2_btree_node_mem_alloc+0x565/0x16f0 fs/bcachefs/btree_cache.c:807
__bch2_btree_node_alloc fs/bcachefs/btree_update_interior.c:304 [inline]
bch2_btree_reserve_get+0x2df/0x1890 fs/bcachefs/btree_update_interior.c:532
bch2_btree_update_start+0xe56/0x14e0 fs/bcachefs/btree_update_interior.c:1230
bch2_btree_split_leaf+0x121/0x880 fs/bcachefs/btree_update_interior.c:1851
bch2_trans_commit_error+0x212/0x1380 fs/bcachefs/btree_trans_commit.c:908
__bch2_trans_commit+0x812b/0x97a0 fs/bcachefs/btree_trans_commit.c:1085
bch2_trans_commit fs/bcachefs/btree_update.h:183 [inline]
bch2_trans_mark_metadata_bucket+0x47a/0x17b0 fs/bcachefs/buckets.c:1043
bch2_trans_mark_metadata_sectors fs/bcachefs/buckets.c:1060 [inline]
__bch2_trans_mark_dev_sb fs/bcachefs/buckets.c:1100 [inline]
bch2_trans_mark_dev_sb+0x3f6/0x820 fs/bcachefs/buckets.c:1128
bch2_trans_mark_dev_sbs_flags+0x6be/0x720 fs/bcachefs/buckets.c:1138
bch2_fs_initialize+0xba0/0x1610 fs/bcachefs/recovery.c:1149
bch2_fs_start+0x36d/0x610 fs/bcachefs/super.c:1042
bch2_fs_get_tree+0xd8d/0x1740 fs/bcachefs/fs.c:2203
vfs_get_tree+0x90/0x2b0 fs/super.c:1814
do_new_mount+0x2be/0xb40 fs/namespace.c:3560
do_mount fs/namespace.c:3900 [inline]
__do_sys_mount fs/namespace.c:4111 [inline]
__se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
pcpu_alloc_mutex --> fs_reclaim --> &bc->lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&bc->lock);
lock(fs_reclaim);
lock(&bc->lock);
lock(pcpu_alloc_mutex);
*** DEADLOCK ***
4 locks held by syz.0.21/5625:
#0: ffff888051400278 (&c->state_lock){+.+.}-{4:4}, at: bch2_fs_start+0x45/0x610 fs/bcachefs/super.c:1010
#1: ffff888051404378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:164 [inline]
#1: ffff888051404378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:256 [inline]
#1: ffff888051404378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: __bch2_trans_get+0x7e4/0xd30 fs/bcachefs/btree_iter.c:3377
#2: ffff8880514266d0 (&c->gc_lock){.+.+}-{4:4}, at: bch2_btree_update_start+0x682/0x14e0 fs/bcachefs/btree_update_interior.c:1180
#3: ffff888051401c68 (&bc->lock){+.+.}-{4:4}, at: bch2_btree_node_mem_alloc+0x559/0x16f0 fs/bcachefs/btree_cache.c:804
stack backtrace:
CPU: 0 UID: 0 PID: 5625 Comm: syz.0.21 Not tainted 6.14.0-rc2-syzkaller-00039-g09fbf3d50205 #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:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2076
check_noncircular+0x36a/0x4a0 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+0x18ef/0x5920 kernel/locking/lockdep.c:3906
__lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
__mutex_lock_common kernel/locking/mutex.c:585 [inline]
__mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
pcpu_alloc_noprof+0x293/0x1760 mm/percpu.c:1782
__six_lock_init+0x104/0x150 fs/bcachefs/six.c:876
bch2_btree_lock_init+0x38/0x100 fs/bcachefs/btree_locking.c:12
bch2_btree_node_mem_alloc+0x565/0x16f0 fs/bcachefs/btree_cache.c:807
__bch2_btree_node_alloc fs/bcachefs/btree_update_interior.c:304 [inline]
bch2_btree_reserve_get+0x2df/0x1890 fs/bcachefs/btree_update_interior.c:532
bch2_btree_update_start+0xe56/0x14e0 fs/bcachefs/btree_update_interior.c:1230
bch2_btree_split_leaf+0x121/0x880 fs/bcachefs/btree_update_interior.c:1851
bch2_trans_commit_error+0x212/0x1380 fs/bcachefs/btree_trans_commit.c:908
__bch2_trans_commit+0x812b/0x97a0 fs/bcachefs/btree_trans_commit.c:1085
bch2_trans_commit fs/bcachefs/btree_update.h:183 [inline]
bch2_trans_mark_metadata_bucket+0x47a/0x17b0 fs/bcachefs/buckets.c:1043
bch2_trans_mark_metadata_sectors fs/bcachefs/buckets.c:1060 [inline]
__bch2_trans_mark_dev_sb fs/bcachefs/buckets.c:1100 [inline]
bch2_trans_mark_dev_sb+0x3f6/0x820 fs/bcachefs/buckets.c:1128
bch2_trans_mark_dev_sbs_flags+0x6be/0x720 fs/bcachefs/buckets.c:1138
bch2_fs_initialize+0xba0/0x1610 fs/bcachefs/recovery.c:1149
bch2_fs_start+0x36d/0x610 fs/bcachefs/super.c:1042
bch2_fs_get_tree+0xd8d/0x1740 fs/bcachefs/fs.c:2203
vfs_get_tree+0x90/0x2b0 fs/super.c:1814
do_new_mount+0x2be/0xb40 fs/namespace.c:3560
do_mount fs/namespace.c:3900 [inline]
__do_sys_mount fs/namespace.c:4111 [inline]
__se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcaed38e58a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007fcaec5fde68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fcaec5fdef0 RCX: 00007fcaed38e58a
RDX: 00004000000000c0 RSI: 0000400000000180 RDI: 00007fcaec5fdeb0
RBP: 00004000000000c0 R08: 00007fcaec5fdef0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000400000000180
R13: 00007fcaec5fdeb0 R14: 0000000000005a05 R15: 0000400000000480
</TASK>
bcachefs (loop0): initializing freespace
bcachefs (loop0): done initializing freespace
bcachefs (loop0): reading snapshots table
bcachefs (loop0): reading snapshots done
bcachefs (loop0): done starting filesystem
---
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] 7+ messages in thread
* Re: [syzbot] [bcachefs?] possible deadlock in pcpu_alloc_noprof
2025-02-12 4:31 ` syzbot
@ 2025-02-12 9:22 ` Alan Huang
2025-02-12 9:49 ` syzbot
2025-02-24 18:52 ` Alan Huang
1 sibling, 1 reply; 7+ messages in thread
From: Alan Huang @ 2025-02-12 9:22 UTC (permalink / raw)
To: syzbot; +Cc: kent.overstreet, linux-bcachefs, linux-kernel, syzkaller-bugs
> On Feb 12, 2025, at 12:31, syzbot <syzbot+fe63f377148a6371a9db@syzkaller.appspotmail.com> wrote:
>
> syzbot has found a reproducer for the following issue on:
>
> HEAD commit: 09fbf3d50205 Merge tag 'tomoyo-pr-20250211' of git://git.c..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=14370aa4580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=3c2347dd6174fbe2
> dashboard link: https://syzkaller.appspot.com/bug?extid=fe63f377148a6371a9db
> 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=17404718580000
>
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-09fbf3d5.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/835b3d29c46c/vmlinux-09fbf3d5.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/ff4bfd8a5d42/bzImage-09fbf3d5.xz
> mounted in repro #1: https://storage.googleapis.com/syzbot-assets/24d046ee591e/mount_7.gz
> mounted in repro #2: https://storage.googleapis.com/syzbot-assets/fc8a49472f19/mount_9.gz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+fe63f377148a6371a9db@syzkaller.appspotmail.com
>
> bcachefs (loop0): initializing new filesystem
> bcachefs (loop0): going read-write
> bcachefs (loop0): marking superblocks
> ======================================================
> WARNING: possible circular locking dependency detected
> 6.14.0-rc2-syzkaller-00039-g09fbf3d50205 #0 Not tainted
> ------------------------------------------------------
> syz.0.21/5625 is trying to acquire lock:
> ffffffff8ea19608 (pcpu_alloc_mutex){+.+.}-{4:4}, at: pcpu_alloc_noprof+0x293/0x1760 mm/percpu.c:1782
>
> but task is already holding lock:
> ffff888051401c68 (&bc->lock){+.+.}-{4:4}, at: bch2_btree_node_mem_alloc+0x559/0x16f0 fs/bcachefs/btree_cache.c:804
>
> which lock already depends on the new lock.
>
>
> the existing dependency chain (in reverse order) is:
>
> -> #2 (&bc->lock){+.+.}-{4:4}:
> lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
> __mutex_lock_common kernel/locking/mutex.c:585 [inline]
> __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
> bch2_btree_cache_scan+0x184/0xec0 fs/bcachefs/btree_cache.c:482
> do_shrink_slab+0x72d/0x1160 mm/shrinker.c:437
> shrink_slab+0x1093/0x14d0 mm/shrinker.c:664
> shrink_one+0x43b/0x850 mm/vmscan.c:4868
> shrink_many mm/vmscan.c:4929 [inline]
> lru_gen_shrink_node mm/vmscan.c:5007 [inline]
> shrink_node+0x37c5/0x3e50 mm/vmscan.c:5978
> kswapd_shrink_node mm/vmscan.c:6807 [inline]
> balance_pgdat mm/vmscan.c:6999 [inline]
> kswapd+0x20f3/0x3b10 mm/vmscan.c:7264
> kthread+0x7a9/0x920 kernel/kthread.c:464
> ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
> ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
>
> -> #1 (fs_reclaim){+.+.}-{0:0}:
> lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
> __fs_reclaim_acquire mm/page_alloc.c:3853 [inline]
> fs_reclaim_acquire+0x88/0x130 mm/page_alloc.c:3867
> might_alloc include/linux/sched/mm.h:318 [inline]
> slab_pre_alloc_hook mm/slub.c:4066 [inline]
> slab_alloc_node mm/slub.c:4144 [inline]
> __do_kmalloc_node mm/slub.c:4293 [inline]
> __kmalloc_noprof+0xae/0x4c0 mm/slub.c:4306
> kmalloc_noprof include/linux/slab.h:905 [inline]
> kzalloc_noprof include/linux/slab.h:1037 [inline]
> pcpu_mem_zalloc mm/percpu.c:510 [inline]
> pcpu_alloc_chunk mm/percpu.c:1430 [inline]
> pcpu_create_chunk+0x57/0xbc0 mm/percpu-vm.c:338
> pcpu_balance_populated mm/percpu.c:2063 [inline]
> pcpu_balance_workfn+0xc4d/0xd40 mm/percpu.c:2200
> process_one_work kernel/workqueue.c:3236 [inline]
> process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317
> worker_thread+0x870/0xd30 kernel/workqueue.c:3398
> kthread+0x7a9/0x920 kernel/kthread.c:464
> ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
> ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
>
> -> #0 (pcpu_alloc_mutex){+.+.}-{4:4}:
> check_prev_add kernel/locking/lockdep.c:3163 [inline]
> check_prevs_add kernel/locking/lockdep.c:3282 [inline]
> validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
> __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
> lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
> __mutex_lock_common kernel/locking/mutex.c:585 [inline]
> __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
> pcpu_alloc_noprof+0x293/0x1760 mm/percpu.c:1782
> __six_lock_init+0x104/0x150 fs/bcachefs/six.c:876
> bch2_btree_lock_init+0x38/0x100 fs/bcachefs/btree_locking.c:12
> bch2_btree_node_mem_alloc+0x565/0x16f0 fs/bcachefs/btree_cache.c:807
> __bch2_btree_node_alloc fs/bcachefs/btree_update_interior.c:304 [inline]
> bch2_btree_reserve_get+0x2df/0x1890 fs/bcachefs/btree_update_interior.c:532
> bch2_btree_update_start+0xe56/0x14e0 fs/bcachefs/btree_update_interior.c:1230
> bch2_btree_split_leaf+0x121/0x880 fs/bcachefs/btree_update_interior.c:1851
> bch2_trans_commit_error+0x212/0x1380 fs/bcachefs/btree_trans_commit.c:908
> __bch2_trans_commit+0x812b/0x97a0 fs/bcachefs/btree_trans_commit.c:1085
> bch2_trans_commit fs/bcachefs/btree_update.h:183 [inline]
> bch2_trans_mark_metadata_bucket+0x47a/0x17b0 fs/bcachefs/buckets.c:1043
> bch2_trans_mark_metadata_sectors fs/bcachefs/buckets.c:1060 [inline]
> __bch2_trans_mark_dev_sb fs/bcachefs/buckets.c:1100 [inline]
> bch2_trans_mark_dev_sb+0x3f6/0x820 fs/bcachefs/buckets.c:1128
> bch2_trans_mark_dev_sbs_flags+0x6be/0x720 fs/bcachefs/buckets.c:1138
> bch2_fs_initialize+0xba0/0x1610 fs/bcachefs/recovery.c:1149
> bch2_fs_start+0x36d/0x610 fs/bcachefs/super.c:1042
> bch2_fs_get_tree+0xd8d/0x1740 fs/bcachefs/fs.c:2203
> vfs_get_tree+0x90/0x2b0 fs/super.c:1814
> do_new_mount+0x2be/0xb40 fs/namespace.c:3560
> do_mount fs/namespace.c:3900 [inline]
> __do_sys_mount fs/namespace.c:4111 [inline]
> __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> other info that might help us debug this:
>
> Chain exists of:
> pcpu_alloc_mutex --> fs_reclaim --> &bc->lock
>
> Possible unsafe locking scenario:
>
> CPU0 CPU1
> ---- ----
> lock(&bc->lock);
> lock(fs_reclaim);
> lock(&bc->lock);
> lock(pcpu_alloc_mutex);
>
> *** DEADLOCK ***
>
> 4 locks held by syz.0.21/5625:
> #0: ffff888051400278 (&c->state_lock){+.+.}-{4:4}, at: bch2_fs_start+0x45/0x610 fs/bcachefs/super.c:1010
> #1: ffff888051404378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:164 [inline]
> #1: ffff888051404378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:256 [inline]
> #1: ffff888051404378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: __bch2_trans_get+0x7e4/0xd30 fs/bcachefs/btree_iter.c:3377
> #2: ffff8880514266d0 (&c->gc_lock){.+.+}-{4:4}, at: bch2_btree_update_start+0x682/0x14e0 fs/bcachefs/btree_update_interior.c:1180
> #3: ffff888051401c68 (&bc->lock){+.+.}-{4:4}, at: bch2_btree_node_mem_alloc+0x559/0x16f0 fs/bcachefs/btree_cache.c:804
>
> stack backtrace:
> CPU: 0 UID: 0 PID: 5625 Comm: syz.0.21 Not tainted 6.14.0-rc2-syzkaller-00039-g09fbf3d50205 #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:94 [inline]
> dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
> print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2076
> check_noncircular+0x36a/0x4a0 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+0x18ef/0x5920 kernel/locking/lockdep.c:3906
> __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
> lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
> __mutex_lock_common kernel/locking/mutex.c:585 [inline]
> __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
> pcpu_alloc_noprof+0x293/0x1760 mm/percpu.c:1782
> __six_lock_init+0x104/0x150 fs/bcachefs/six.c:876
> bch2_btree_lock_init+0x38/0x100 fs/bcachefs/btree_locking.c:12
> bch2_btree_node_mem_alloc+0x565/0x16f0 fs/bcachefs/btree_cache.c:807
> __bch2_btree_node_alloc fs/bcachefs/btree_update_interior.c:304 [inline]
> bch2_btree_reserve_get+0x2df/0x1890 fs/bcachefs/btree_update_interior.c:532
> bch2_btree_update_start+0xe56/0x14e0 fs/bcachefs/btree_update_interior.c:1230
> bch2_btree_split_leaf+0x121/0x880 fs/bcachefs/btree_update_interior.c:1851
> bch2_trans_commit_error+0x212/0x1380 fs/bcachefs/btree_trans_commit.c:908
> __bch2_trans_commit+0x812b/0x97a0 fs/bcachefs/btree_trans_commit.c:1085
> bch2_trans_commit fs/bcachefs/btree_update.h:183 [inline]
> bch2_trans_mark_metadata_bucket+0x47a/0x17b0 fs/bcachefs/buckets.c:1043
> bch2_trans_mark_metadata_sectors fs/bcachefs/buckets.c:1060 [inline]
> __bch2_trans_mark_dev_sb fs/bcachefs/buckets.c:1100 [inline]
> bch2_trans_mark_dev_sb+0x3f6/0x820 fs/bcachefs/buckets.c:1128
> bch2_trans_mark_dev_sbs_flags+0x6be/0x720 fs/bcachefs/buckets.c:1138
> bch2_fs_initialize+0xba0/0x1610 fs/bcachefs/recovery.c:1149
> bch2_fs_start+0x36d/0x610 fs/bcachefs/super.c:1042
> bch2_fs_get_tree+0xd8d/0x1740 fs/bcachefs/fs.c:2203
> vfs_get_tree+0x90/0x2b0 fs/super.c:1814
> do_new_mount+0x2be/0xb40 fs/namespace.c:3560
> do_mount fs/namespace.c:3900 [inline]
> __do_sys_mount fs/namespace.c:4111 [inline]
> __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7fcaed38e58a
> Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007fcaec5fde68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
> RAX: ffffffffffffffda RBX: 00007fcaec5fdef0 RCX: 00007fcaed38e58a
> RDX: 00004000000000c0 RSI: 0000400000000180 RDI: 00007fcaec5fdeb0
> RBP: 00004000000000c0 R08: 00007fcaec5fdef0 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000400000000180
> R13: 00007fcaec5fdeb0 R14: 0000000000005a05 R15: 0000400000000480
> </TASK>
> bcachefs (loop0): initializing freespace
> bcachefs (loop0): done initializing freespace
> bcachefs (loop0): reading snapshots table
> bcachefs (loop0): reading snapshots done
> bcachefs (loop0): done starting filesystem
>
>
> ---
> 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.
>
#syz test
diff --git a/fs/bcachefs/six.c b/fs/bcachefs/six.c
index 7e7c66a1e1a6..ccdc6d496910 100644
--- a/fs/bcachefs/six.c
+++ b/fs/bcachefs/six.c
@@ -873,7 +873,7 @@ void __six_lock_init(struct six_lock *lock, const char *name,
* failure if they wish by checking lock->readers, but generally
* will not want to treat it as an error.
*/
- lock->readers = alloc_percpu(unsigned);
+ lock->readers = alloc_percpu_gfp(unsigned, GFP_NOWAIT|__GFP_NOWARN);
}
#endif
}
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [syzbot] [bcachefs?] possible deadlock in pcpu_alloc_noprof
2025-02-12 9:22 ` Alan Huang
@ 2025-02-12 9:49 ` syzbot
0 siblings, 0 replies; 7+ messages in thread
From: syzbot @ 2025-02-12 9:49 UTC (permalink / raw)
To: kent.overstreet, linux-bcachefs, linux-kernel, mmpgouride,
syzkaller-bugs
Hello,
syzbot has tested the proposed patch and the reproducer did not trigger any issue:
Reported-by: syzbot+fe63f377148a6371a9db@syzkaller.appspotmail.com
Tested-by: syzbot+fe63f377148a6371a9db@syzkaller.appspotmail.com
Tested on:
commit: 09fbf3d5 Merge tag 'tomoyo-pr-20250211' of git://git.c..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13cba3f8580000
kernel config: https://syzkaller.appspot.com/x/.config?x=3c2347dd6174fbe2
dashboard link: https://syzkaller.appspot.com/bug?extid=fe63f377148a6371a9db
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=12f28aa4580000
Note: testing is done by a robot and is best-effort only.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [syzbot] [bcachefs?] possible deadlock in pcpu_alloc_noprof
2025-02-12 4:31 ` syzbot
2025-02-12 9:22 ` Alan Huang
@ 2025-02-24 18:52 ` Alan Huang
2025-02-24 19:17 ` syzbot
1 sibling, 1 reply; 7+ messages in thread
From: Alan Huang @ 2025-02-24 18:52 UTC (permalink / raw)
To: syzbot; +Cc: kent.overstreet, linux-bcachefs, linux-kernel, syzkaller-bugs
> On Feb 12, 2025, at 12:31, syzbot <syzbot+fe63f377148a6371a9db@syzkaller.appspotmail.com> wrote:
>
> syzbot has found a reproducer for the following issue on:
>
> HEAD commit: 09fbf3d50205 Merge tag 'tomoyo-pr-20250211' of git://git.c..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=14370aa4580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=3c2347dd6174fbe2
> dashboard link: https://syzkaller.appspot.com/bug?extid=fe63f377148a6371a9db
> 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=17404718580000
>
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-09fbf3d5.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/835b3d29c46c/vmlinux-09fbf3d5.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/ff4bfd8a5d42/bzImage-09fbf3d5.xz
> mounted in repro #1: https://storage.googleapis.com/syzbot-assets/24d046ee591e/mount_7.gz
> mounted in repro #2: https://storage.googleapis.com/syzbot-assets/fc8a49472f19/mount_9.gz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+fe63f377148a6371a9db@syzkaller.appspotmail.com
>
> bcachefs (loop0): initializing new filesystem
> bcachefs (loop0): going read-write
> bcachefs (loop0): marking superblocks
> ======================================================
> WARNING: possible circular locking dependency detected
> 6.14.0-rc2-syzkaller-00039-g09fbf3d50205 #0 Not tainted
> ------------------------------------------------------
> syz.0.21/5625 is trying to acquire lock:
> ffffffff8ea19608 (pcpu_alloc_mutex){+.+.}-{4:4}, at: pcpu_alloc_noprof+0x293/0x1760 mm/percpu.c:1782
>
> but task is already holding lock:
> ffff888051401c68 (&bc->lock){+.+.}-{4:4}, at: bch2_btree_node_mem_alloc+0x559/0x16f0 fs/bcachefs/btree_cache.c:804
>
> which lock already depends on the new lock.
>
>
> the existing dependency chain (in reverse order) is:
>
> -> #2 (&bc->lock){+.+.}-{4:4}:
> lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
> __mutex_lock_common kernel/locking/mutex.c:585 [inline]
> __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
> bch2_btree_cache_scan+0x184/0xec0 fs/bcachefs/btree_cache.c:482
> do_shrink_slab+0x72d/0x1160 mm/shrinker.c:437
> shrink_slab+0x1093/0x14d0 mm/shrinker.c:664
> shrink_one+0x43b/0x850 mm/vmscan.c:4868
> shrink_many mm/vmscan.c:4929 [inline]
> lru_gen_shrink_node mm/vmscan.c:5007 [inline]
> shrink_node+0x37c5/0x3e50 mm/vmscan.c:5978
> kswapd_shrink_node mm/vmscan.c:6807 [inline]
> balance_pgdat mm/vmscan.c:6999 [inline]
> kswapd+0x20f3/0x3b10 mm/vmscan.c:7264
> kthread+0x7a9/0x920 kernel/kthread.c:464
> ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
> ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
>
> -> #1 (fs_reclaim){+.+.}-{0:0}:
> lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
> __fs_reclaim_acquire mm/page_alloc.c:3853 [inline]
> fs_reclaim_acquire+0x88/0x130 mm/page_alloc.c:3867
> might_alloc include/linux/sched/mm.h:318 [inline]
> slab_pre_alloc_hook mm/slub.c:4066 [inline]
> slab_alloc_node mm/slub.c:4144 [inline]
> __do_kmalloc_node mm/slub.c:4293 [inline]
> __kmalloc_noprof+0xae/0x4c0 mm/slub.c:4306
> kmalloc_noprof include/linux/slab.h:905 [inline]
> kzalloc_noprof include/linux/slab.h:1037 [inline]
> pcpu_mem_zalloc mm/percpu.c:510 [inline]
> pcpu_alloc_chunk mm/percpu.c:1430 [inline]
> pcpu_create_chunk+0x57/0xbc0 mm/percpu-vm.c:338
> pcpu_balance_populated mm/percpu.c:2063 [inline]
> pcpu_balance_workfn+0xc4d/0xd40 mm/percpu.c:2200
> process_one_work kernel/workqueue.c:3236 [inline]
> process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317
> worker_thread+0x870/0xd30 kernel/workqueue.c:3398
> kthread+0x7a9/0x920 kernel/kthread.c:464
> ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
> ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
>
> -> #0 (pcpu_alloc_mutex){+.+.}-{4:4}:
> check_prev_add kernel/locking/lockdep.c:3163 [inline]
> check_prevs_add kernel/locking/lockdep.c:3282 [inline]
> validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
> __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
> lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
> __mutex_lock_common kernel/locking/mutex.c:585 [inline]
> __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
> pcpu_alloc_noprof+0x293/0x1760 mm/percpu.c:1782
> __six_lock_init+0x104/0x150 fs/bcachefs/six.c:876
> bch2_btree_lock_init+0x38/0x100 fs/bcachefs/btree_locking.c:12
> bch2_btree_node_mem_alloc+0x565/0x16f0 fs/bcachefs/btree_cache.c:807
> __bch2_btree_node_alloc fs/bcachefs/btree_update_interior.c:304 [inline]
> bch2_btree_reserve_get+0x2df/0x1890 fs/bcachefs/btree_update_interior.c:532
> bch2_btree_update_start+0xe56/0x14e0 fs/bcachefs/btree_update_interior.c:1230
> bch2_btree_split_leaf+0x121/0x880 fs/bcachefs/btree_update_interior.c:1851
> bch2_trans_commit_error+0x212/0x1380 fs/bcachefs/btree_trans_commit.c:908
> __bch2_trans_commit+0x812b/0x97a0 fs/bcachefs/btree_trans_commit.c:1085
> bch2_trans_commit fs/bcachefs/btree_update.h:183 [inline]
> bch2_trans_mark_metadata_bucket+0x47a/0x17b0 fs/bcachefs/buckets.c:1043
> bch2_trans_mark_metadata_sectors fs/bcachefs/buckets.c:1060 [inline]
> __bch2_trans_mark_dev_sb fs/bcachefs/buckets.c:1100 [inline]
> bch2_trans_mark_dev_sb+0x3f6/0x820 fs/bcachefs/buckets.c:1128
> bch2_trans_mark_dev_sbs_flags+0x6be/0x720 fs/bcachefs/buckets.c:1138
> bch2_fs_initialize+0xba0/0x1610 fs/bcachefs/recovery.c:1149
> bch2_fs_start+0x36d/0x610 fs/bcachefs/super.c:1042
> bch2_fs_get_tree+0xd8d/0x1740 fs/bcachefs/fs.c:2203
> vfs_get_tree+0x90/0x2b0 fs/super.c:1814
> do_new_mount+0x2be/0xb40 fs/namespace.c:3560
> do_mount fs/namespace.c:3900 [inline]
> __do_sys_mount fs/namespace.c:4111 [inline]
> __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> other info that might help us debug this:
>
> Chain exists of:
> pcpu_alloc_mutex --> fs_reclaim --> &bc->lock
>
> Possible unsafe locking scenario:
>
> CPU0 CPU1
> ---- ----
> lock(&bc->lock);
> lock(fs_reclaim);
> lock(&bc->lock);
> lock(pcpu_alloc_mutex);
>
> *** DEADLOCK ***
>
> 4 locks held by syz.0.21/5625:
> #0: ffff888051400278 (&c->state_lock){+.+.}-{4:4}, at: bch2_fs_start+0x45/0x610 fs/bcachefs/super.c:1010
> #1: ffff888051404378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:164 [inline]
> #1: ffff888051404378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:256 [inline]
> #1: ffff888051404378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: __bch2_trans_get+0x7e4/0xd30 fs/bcachefs/btree_iter.c:3377
> #2: ffff8880514266d0 (&c->gc_lock){.+.+}-{4:4}, at: bch2_btree_update_start+0x682/0x14e0 fs/bcachefs/btree_update_interior.c:1180
> #3: ffff888051401c68 (&bc->lock){+.+.}-{4:4}, at: bch2_btree_node_mem_alloc+0x559/0x16f0 fs/bcachefs/btree_cache.c:804
>
> stack backtrace:
> CPU: 0 UID: 0 PID: 5625 Comm: syz.0.21 Not tainted 6.14.0-rc2-syzkaller-00039-g09fbf3d50205 #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:94 [inline]
> dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
> print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2076
> check_noncircular+0x36a/0x4a0 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+0x18ef/0x5920 kernel/locking/lockdep.c:3906
> __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
> lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
> __mutex_lock_common kernel/locking/mutex.c:585 [inline]
> __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
> pcpu_alloc_noprof+0x293/0x1760 mm/percpu.c:1782
> __six_lock_init+0x104/0x150 fs/bcachefs/six.c:876
> bch2_btree_lock_init+0x38/0x100 fs/bcachefs/btree_locking.c:12
> bch2_btree_node_mem_alloc+0x565/0x16f0 fs/bcachefs/btree_cache.c:807
> __bch2_btree_node_alloc fs/bcachefs/btree_update_interior.c:304 [inline]
> bch2_btree_reserve_get+0x2df/0x1890 fs/bcachefs/btree_update_interior.c:532
> bch2_btree_update_start+0xe56/0x14e0 fs/bcachefs/btree_update_interior.c:1230
> bch2_btree_split_leaf+0x121/0x880 fs/bcachefs/btree_update_interior.c:1851
> bch2_trans_commit_error+0x212/0x1380 fs/bcachefs/btree_trans_commit.c:908
> __bch2_trans_commit+0x812b/0x97a0 fs/bcachefs/btree_trans_commit.c:1085
> bch2_trans_commit fs/bcachefs/btree_update.h:183 [inline]
> bch2_trans_mark_metadata_bucket+0x47a/0x17b0 fs/bcachefs/buckets.c:1043
> bch2_trans_mark_metadata_sectors fs/bcachefs/buckets.c:1060 [inline]
> __bch2_trans_mark_dev_sb fs/bcachefs/buckets.c:1100 [inline]
> bch2_trans_mark_dev_sb+0x3f6/0x820 fs/bcachefs/buckets.c:1128
> bch2_trans_mark_dev_sbs_flags+0x6be/0x720 fs/bcachefs/buckets.c:1138
> bch2_fs_initialize+0xba0/0x1610 fs/bcachefs/recovery.c:1149
> bch2_fs_start+0x36d/0x610 fs/bcachefs/super.c:1042
> bch2_fs_get_tree+0xd8d/0x1740 fs/bcachefs/fs.c:2203
> vfs_get_tree+0x90/0x2b0 fs/super.c:1814
> do_new_mount+0x2be/0xb40 fs/namespace.c:3560
> do_mount fs/namespace.c:3900 [inline]
> __do_sys_mount fs/namespace.c:4111 [inline]
> __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7fcaed38e58a
> Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007fcaec5fde68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
> RAX: ffffffffffffffda RBX: 00007fcaec5fdef0 RCX: 00007fcaed38e58a
> RDX: 00004000000000c0 RSI: 0000400000000180 RDI: 00007fcaec5fdeb0
> RBP: 00004000000000c0 R08: 00007fcaec5fdef0 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000400000000180
> R13: 00007fcaec5fdeb0 R14: 0000000000005a05 R15: 0000400000000480
> </TASK>
> bcachefs (loop0): initializing freespace
> bcachefs (loop0): done initializing freespace
> bcachefs (loop0): reading snapshots table
> bcachefs (loop0): reading snapshots done
> bcachefs (loop0): done starting filesystem
>
>
> ---
> 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.
>
#syz test
diff --git a/fs/bcachefs/btree_cache.c b/fs/bcachefs/btree_cache.c
index ca755e8d1a37..9761dc05ba07 100644
--- a/fs/bcachefs/btree_cache.c
+++ b/fs/bcachefs/btree_cache.c
@@ -794,17 +794,17 @@ struct btree *bch2_btree_node_mem_alloc(struct btree_trans *trans, bool pcpu_rea
goto got_node;
}
+ mutex_unlock(&bc->lock);
b = __btree_node_mem_alloc(c, GFP_NOWAIT|__GFP_NOWARN);
if (!b) {
- mutex_unlock(&bc->lock);
bch2_trans_unlock(trans);
b = __btree_node_mem_alloc(c, GFP_KERNEL);
if (!b)
goto err;
- mutex_lock(&bc->lock);
}
bch2_btree_lock_init(&b->c, pcpu_read_locks ? SIX_LOCK_INIT_PCPU : 0);
+ mutex_lock(&bc->lock);
BUG_ON(!six_trylock_intent(&b->c.lock));
BUG_ON(!six_trylock_write(&b->c.lock));
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [syzbot] [bcachefs?] possible deadlock in pcpu_alloc_noprof
2025-02-24 18:52 ` Alan Huang
@ 2025-02-24 19:17 ` syzbot
0 siblings, 0 replies; 7+ messages in thread
From: syzbot @ 2025-02-24 19:17 UTC (permalink / raw)
To: kent.overstreet, linux-bcachefs, linux-kernel, mmpgouride,
syzkaller-bugs
Hello,
syzbot has tested the proposed patch and the reproducer did not trigger any issue:
Reported-by: syzbot+fe63f377148a6371a9db@syzkaller.appspotmail.com
Tested-by: syzbot+fe63f377148a6371a9db@syzkaller.appspotmail.com
Tested on:
commit: d082ecbc Linux 6.14-rc4
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=133946e4580000
kernel config: https://syzkaller.appspot.com/x/.config?x=8dcce427a3afb99b
dashboard link: https://syzkaller.appspot.com/bug?extid=fe63f377148a6371a9db
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=1576adb0580000
Note: testing is done by a robot and is best-effort only.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [syzbot] [bcachefs?] possible deadlock in pcpu_alloc_noprof
2024-09-29 16:17 [syzbot] [bcachefs?] possible deadlock in pcpu_alloc_noprof syzbot
2025-02-12 4:31 ` syzbot
@ 2025-05-29 9:09 ` syzbot
1 sibling, 0 replies; 7+ messages in thread
From: syzbot @ 2025-05-29 9:09 UTC (permalink / raw)
To: axboe, cl, dennis, kent.overstreet, linux-bcachefs, linux-block,
linux-kernel, linux-mm, mhocko, mmpgouride, syzkaller-bugs, tj,
vbabka
syzbot has found a reproducer for the following issue on:
HEAD commit: 90b83efa6701 Merge tag 'bpf-next-6.16' of git://git.kernel..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=145b4ed4580000
kernel config: https://syzkaller.appspot.com/x/.config?x=fbd871027e10b130
dashboard link: https://syzkaller.appspot.com/bug?extid=fe63f377148a6371a9db
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=166807f4580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=125b4ed4580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7b23158542c6/disk-90b83efa.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fe77cd0d7150/vmlinux-90b83efa.xz
kernel image: https://storage.googleapis.com/syzbot-assets/fdddbd2ed303/bzImage-90b83efa.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fe63f377148a6371a9db@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
6.15.0-syzkaller-07774-g90b83efa6701 #0 Not tainted
------------------------------------------------------
syz-executor398/5854 is trying to acquire lock:
ffffffff8e52d3a8 (pcpu_alloc_mutex){+.+.}-{4:4}, at: pcpu_alloc_noprof+0xb4a/0x1470 mm/percpu.c:1782
but task is already holding lock:
ffff88814333d8b0 (&q->q_usage_counter(io)#58){++++}-{0:0}, at: blk_mq_freeze_queue_nomemsave+0x15/0x20 block/blk-mq.c:205
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&q->q_usage_counter(io)#58){++++}-{0:0}:
blk_alloc_queue+0x619/0x760 block/blk-core.c:461
blk_mq_alloc_queue+0x175/0x290 block/blk-mq.c:4396
__blk_mq_alloc_disk+0x29/0x120 block/blk-mq.c:4443
nbd_dev_add+0x4a0/0xbc0 drivers/block/nbd.c:1933
nbd_init+0x181/0x320 drivers/block/nbd.c:2670
do_one_initcall+0x120/0x6e0 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+0x5c2/0x900 init/main.c:1567
kernel_init+0x1c/0x2b0 init/main.c:1457
ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #1 (fs_reclaim){+.+.}-{0:0}:
__fs_reclaim_acquire mm/page_alloc.c:4056 [inline]
fs_reclaim_acquire+0x102/0x150 mm/page_alloc.c:4070
might_alloc include/linux/sched/mm.h:318 [inline]
prepare_alloc_pages+0x162/0x610 mm/page_alloc.c:4738
__alloc_frozen_pages_noprof+0x18b/0x23f0 mm/page_alloc.c:4959
__alloc_pages_noprof+0xb/0x1b0 mm/page_alloc.c:5004
__alloc_pages_node_noprof include/linux/gfp.h:284 [inline]
alloc_pages_node_noprof include/linux/gfp.h:311 [inline]
pcpu_alloc_pages mm/percpu-vm.c:95 [inline]
pcpu_populate_chunk+0x110/0xb00 mm/percpu-vm.c:285
pcpu_alloc_noprof+0x86a/0x1470 mm/percpu.c:1870
xt_percpu_counter_alloc+0x13e/0x1b0 net/netfilter/x_tables.c:1931
find_check_entry.constprop.0+0xbc/0x9b0 net/ipv4/netfilter/ip_tables.c:526
translate_table+0xc98/0x1720 net/ipv4/netfilter/ip_tables.c:716
ipt_register_table+0x102/0x430 net/ipv4/netfilter/ip_tables.c:1742
iptable_raw_table_init+0x63/0x90 net/ipv4/netfilter/iptable_raw.c:49
xt_find_table_lock+0x2e1/0x520 net/netfilter/x_tables.c:1260
xt_request_find_table_lock+0x28/0xf0 net/netfilter/x_tables.c:1285
get_info+0x190/0x610 net/ipv4/netfilter/ip_tables.c:963
do_ipt_get_ctl+0x169/0xa10 net/ipv4/netfilter/ip_tables.c:1659
nf_getsockopt+0x7c/0xe0 net/netfilter/nf_sockopt.c:116
ip_getsockopt+0x18c/0x1e0 net/ipv4/ip_sockglue.c:1777
tcp_getsockopt+0x9e/0x100 net/ipv4/tcp.c:4760
do_sock_getsockopt+0x3ff/0x800 net/socket.c:2357
__sys_getsockopt+0x123/0x1b0 net/socket.c:2386
__do_sys_getsockopt net/socket.c:2393 [inline]
__se_sys_getsockopt net/socket.c:2390 [inline]
__x64_sys_getsockopt+0xbd/0x160 net/socket.c:2390
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (pcpu_alloc_mutex){+.+.}-{4:4}:
check_prev_add kernel/locking/lockdep.c:3168 [inline]
check_prevs_add kernel/locking/lockdep.c:3287 [inline]
validate_chain kernel/locking/lockdep.c:3911 [inline]
__lock_acquire+0x126f/0x1c90 kernel/locking/lockdep.c:5240
lock_acquire kernel/locking/lockdep.c:5871 [inline]
lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828
__mutex_lock_common kernel/locking/mutex.c:601 [inline]
__mutex_lock+0x199/0xb90 kernel/locking/mutex.c:746
pcpu_alloc_noprof+0xb4a/0x1470 mm/percpu.c:1782
blk_stat_alloc_callback+0xc8/0x280 block/blk-stat.c:116
wbt_init+0xac/0x540 block/blk-wbt.c:903
queue_wb_lat_store+0x354/0x3d0 block/blk-sysfs.c:603
queue_attr_store+0x276/0x320 block/blk-sysfs.c:805
sysfs_kf_write+0xef/0x150 fs/sysfs/file.c:145
kernfs_fop_write_iter+0x354/0x510 fs/kernfs/file.c:334
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x6c7/0x1150 fs/read_write.c:686
ksys_write+0x12a/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
pcpu_alloc_mutex --> fs_reclaim --> &q->q_usage_counter(io)#58
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&q->q_usage_counter(io)#58);
lock(fs_reclaim);
lock(&q->q_usage_counter(io)#58);
lock(pcpu_alloc_mutex);
*** DEADLOCK ***
5 locks held by syz-executor398/5854:
#0: ffff8880316b8428 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff88802a508088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x510 fs/kernfs/file.c:325
#2: ffff888147e9ac38 (kn->active#57){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2b2/0x510 fs/kernfs/file.c:326
#3: ffff88814333d8b0 (&q->q_usage_counter(io)#58){++++}-{0:0}, at: blk_mq_freeze_queue_nomemsave+0x15/0x20 block/blk-mq.c:205
#4: ffff88814333d8e8 (&q->q_usage_counter(queue)#10){+.+.}-{0:0}, at: blk_mq_freeze_queue_nomemsave+0x15/0x20 block/blk-mq.c:205
stack backtrace:
CPU: 1 UID: 0 PID: 5854 Comm: syz-executor398 Not tainted 6.15.0-syzkaller-07774-g90b83efa6701 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_circular_bug+0x275/0x350 kernel/locking/lockdep.c:2046
check_noncircular+0x14c/0x170 kernel/locking/lockdep.c:2178
check_prev_add kernel/locking/lockdep.c:3168 [inline]
check_prevs_add kernel/locking/lockdep.c:3287 [inline]
validate_chain kernel/locking/lockdep.c:3911 [inline]
__lock_acquire+0x126f/0x1c90 kernel/locking/lockdep.c:5240
lock_acquire kernel/locking/lockdep.c:5871 [inline]
lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828
__mutex_lock_common kernel/locking/mutex.c:601 [inline]
__mutex_lock+0x199/0xb90 kernel/locking/mutex.c:746
pcpu_alloc_noprof+0xb4a/0x1470 mm/percpu.c:1782
blk_stat_alloc_callback+0xc8/0x280 block/blk-stat.c:116
wbt_init+0xac/0x540 block/blk-wbt.c:903
queue_wb_lat_store+0x354/0x3d0 block/blk-sysfs.c:603
queue_attr_store+0x276/0x320 block/blk-sysfs.c:805
sysfs_kf_write+0xef/0x150 fs/sysfs/file.c:145
kernfs_fop_write_iter+0x354/0x510 fs/kernfs/file.c:334
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x6c7/0x1150 fs/read_write.c:686
ksys_write+0x12a/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f18df4b0e49
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 1d 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc61925058 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f18df4b0e49
RDX: 0000000000000801 RSI: 0000200000000240 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007ffc61925090 R14: 00007ffc619250d0 R15: 0000000000000000
</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.
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2025-05-29 9:09 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2024-09-29 16:17 [syzbot] [bcachefs?] possible deadlock in pcpu_alloc_noprof syzbot
2025-02-12 4:31 ` syzbot
2025-02-12 9:22 ` Alan Huang
2025-02-12 9:49 ` syzbot
2025-02-24 18:52 ` Alan Huang
2025-02-24 19:17 ` syzbot
2025-05-29 9:09 ` syzbot
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