* [syzbot] [ext4?] INFO: task hung in block_read_full_folio (3)
@ 2026-02-11 16:37 syzbot
2026-02-26 9:36 ` syzbot
0 siblings, 1 reply; 2+ messages in thread
From: syzbot @ 2026-02-11 16:37 UTC (permalink / raw)
To: adilger.kernel, linux-ext4, linux-kernel, syzkaller-bugs, tytso
Hello,
syzbot found the following issue on:
HEAD commit: 2687c848e578 x86/vmware: Fix hypercall clobbers
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=158c2a5a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e3161cabe5a361ff
dashboard link: https://syzkaller.appspot.com/bug?extid=03afbb29537f0336b7ad
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=131aab22580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/988f106eda78/disk-2687c848.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/52aad858e7e7/vmlinux-2687c848.xz
kernel image: https://storage.googleapis.com/syzbot-assets/99f1cbe5967b/bzImage-2687c848.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/405f0d179069/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=16a9265a580000)
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+03afbb29537f0336b7ad@syzkaller.appspotmail.com
INFO: task syz.3.1794:12741 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.1794 state:D stack:23768 pid:12741 tgid:12736 ppid:5962 task_flags:0x400140 flags:0x00080002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5260 [inline]
__schedule+0x14ea/0x5050 kernel/sched/core.c:6867
__schedule_loop kernel/sched/core.c:6949 [inline]
schedule+0x164/0x360 kernel/sched/core.c:6964
io_schedule+0x7f/0xd0 kernel/sched/core.c:7791
bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:250
__wait_on_bit_lock+0xec/0x4e0 kernel/sched/wait_bit.c:93
out_of_line_wait_on_bit_lock+0x13b/0x190 kernel/sched/wait_bit.c:120
wait_on_bit_lock_io include/linux/wait_bit.h:221 [inline]
__lock_buffer fs/buffer.c:71 [inline]
lock_buffer include/linux/buffer_head.h:432 [inline]
block_read_full_folio+0x38f/0x830 fs/buffer.c:2439
filemap_read_folio+0x137/0x3b0 mm/filemap.c:2496
do_read_cache_folio+0x358/0x590 mm/filemap.c:4096
read_mapping_folio include/linux/pagemap.h:1028 [inline]
read_part_sector+0xb6/0x2b0 block/partitions/core.c:722
amiga_partition+0xe0/0x1dd0 block/partitions/amiga.c:53
check_partition block/partitions/core.c:141 [inline]
blk_add_partitions block/partitions/core.c:589 [inline]
bdev_disk_changed+0x765/0x14c0 block/partitions/core.c:693
loop_reread_partitions drivers/block/loop.c:448 [inline]
loop_set_status+0x9ab/0xe40 drivers/block/loop.c:1277
loop_set_status64 drivers/block/loop.c:1373 [inline]
lo_ioctl+0xc21/0x1fb0 drivers/block/loop.c:1559
blkdev_ioctl+0x5e3/0x740 block/ioctl.c:792
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0918d9aeb9
RSP: 002b:00007f0919c77028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f0919015fa0 RCX: 00007f0918d9aeb9
RDX: 00002000000003c0 RSI: 0000000000004c04 RDI: 0000000000000005
RBP: 00007f0918e08c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0919016038 R14: 00007f0919015fa0 R15: 00007ffe22744b08
</TASK>
INFO: task syz.3.1794:12749 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.1794 state:D stack:22936 pid:12749 tgid:12736 ppid:5962 task_flags:0x440140 flags:0x00080002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5260 [inline]
__schedule+0x14ea/0x5050 kernel/sched/core.c:6867
__schedule_loop kernel/sched/core.c:6949 [inline]
schedule+0x164/0x360 kernel/sched/core.c:6964
io_schedule+0x7f/0xd0 kernel/sched/core.c:7791
folio_wait_bit_common+0x6d8/0xbc0 mm/filemap.c:1323
folio_lock include/linux/pagemap.h:1170 [inline]
__find_get_block_slow fs/buffer.c:205 [inline]
find_get_block_common+0x23c/0xe60 fs/buffer.c:1408
bdev_getblk+0x53/0x6e0 include/linux/gfp.h:-1
__getblk include/linux/buffer_head.h:380 [inline]
sb_getblk include/linux/buffer_head.h:386 [inline]
__ext4_get_inode_loc+0x7d8/0xfa0 fs/ext4/inode.c:4860
ext4_get_inode_loc fs/ext4/inode.c:4963 [inline]
ext4_reserve_inode_write+0x18b/0x360 fs/ext4/inode.c:6287
__ext4_mark_inode_dirty+0x14b/0x6e0 fs/ext4/inode.c:6465
ext4_ext_insert_extent+0x2062/0x4b50 fs/ext4/extents.c:2192
ext4_ext_map_blocks+0x19d1/0x6b80 fs/ext4/extents.c:4404
ext4_map_create_blocks fs/ext4/inode.c:613 [inline]
ext4_map_blocks+0x8da/0x1830 fs/ext4/inode.c:816
ext4_getblk+0x1ca/0x780 fs/ext4/inode.c:984
ext4_bread+0x2a/0x180 fs/ext4/inode.c:1047
ext4_quota_write+0x239/0x580 fs/ext4/super.c:7350
write_blk fs/quota/quota_tree.c:70 [inline]
get_free_dqblk+0x368/0x720 fs/quota/quota_tree.c:136
do_insert_tree+0x256/0x11d0 fs/quota/quota_tree.c:347
do_insert_tree+0x9d7/0x11d0 fs/quota/quota_tree.c:402
do_insert_tree+0x9b2/0x11d0 fs/quota/quota_tree.c:402
do_insert_tree+0x9b2/0x11d0 fs/quota/quota_tree.c:402
dq_insert_tree fs/quota/quota_tree.c:432 [inline]
qtree_write_dquot+0x4b1/0x5e0 fs/quota/quota_tree.c:451
v2_write_dquot+0x183/0x260 fs/quota/quota_v2.c:372
dquot_acquire+0x328/0x620 fs/quota/dquot.c:473
ext4_acquire_dquot+0x2e9/0x4c0 fs/ext4/super.c:6982
dqget+0x7b1/0xf10 fs/quota/dquot.c:980
__dquot_initialize+0x3ba/0xd30 fs/quota/dquot.c:1508
ext4_xattr_set+0xdb/0x340 fs/ext4/xattr.c:2543
__vfs_setxattr+0x43c/0x480 fs/xattr.c:200
__vfs_setxattr_noperm+0x12d/0x660 fs/xattr.c:234
vfs_setxattr+0x16a/0x2e0 fs/xattr.c:321
do_setxattr fs/xattr.c:636 [inline]
filename_setxattr+0x281/0x630 fs/xattr.c:665
path_setxattrat+0x3f3/0x430 fs/xattr.c:713
__do_sys_lsetxattr fs/xattr.c:754 [inline]
__se_sys_lsetxattr fs/xattr.c:750 [inline]
__x64_sys_lsetxattr+0xbf/0xe0 fs/xattr.c:750
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0918d9aeb9
RSP: 002b:00007f0919c56028 EFLAGS: 00000246 ORIG_RAX: 00000000000000bd
RAX: ffffffffffffffda RBX: 00007f0919016090 RCX: 00007f0918d9aeb9
RDX: 0000000000000000 RSI: 00002000000001c0 RDI: 0000200000000180
RBP: 00007f0918e08c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0919016128 R14: 00007f0919016090 R15: 00007ffe22744b08
</TASK>
Showing all locks held in the system:
1 lock held by khungtaskd/32:
#0: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by udevd/5187:
#0:
ffff8881423cc358
(&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962
#1:
ffff8881423cb448
(
&lo->lo_mutex
){+.+.}-{4:4}, at: lo_open+0x4f/0xd0 drivers/block/loop.c:1721
2 locks held by getty/5574:
#0: ffff88814e76c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/5970:
#0: ffffffff8e560c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#0: ffffffff8e560c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:956
1 lock held by udevd/10512:
#0: ffff8881423cc358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962
1 lock held by udevd/10515:
#0: ffff888148c4e3a8 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1042 [inline]
#0: ffff888148c4e3a8 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:855
1 lock held by syz.3.1794/12741:
#0: ffff8880247da358 (&disk->open_mutex){+.+.}-{4:4}, at: loop_reread_partitions drivers/block/loop.c:447 [inline]
#0: ffff8880247da358 (&disk->open_mutex){+.+.}-{4:4}, at: loop_set_status+0x986/0xe40 drivers/block/loop.c:1277
5 locks held by syz.3.1794/12749:
#0: ffff888031f7e420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:499
#1: ffff888060996420 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline]
#1: ffff888060996420 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: vfs_setxattr+0x143/0x2e0 fs/xattr.c:320
#2: ffff88805edd7228 (&dquot->dq_lock){+.+.}-{4:4}, at: dquot_acquire+0x67/0x620 fs/quota/dquot.c:461
#3: ffff888031f7e208 (&s->s_dquot.dqio_sem){++++}-{4:4}, at: v2_write_dquot+0xab/0x260 fs/quota/quota_v2.c:367
#4: ffff888060990c10 (&ei->i_data_sem/2){++++}-{4:4}, at: ext4_map_blocks+0x7d7/0x1830 fs/ext4/inode.c:815
2 locks held by ext4lazyinit/15775:
#0: ffff88805aa420e0 (&type->s_umount_key#31){++++}-{4:4}, at: ext4_lazyinit_thread+0x1b7/0x1830 fs/ext4/super.c:3818
#1: ffff88805aa42420 (sb_writers#4){.+.+}-{0:0}, at: kthread+0x726/0x8b0 kernel/kthread.c:463
3 locks held by syz.1.3370/18614:
#0: ffff8881423cb448 (&lo->lo_mutex){+.+.}-{4:4}, at: loop_set_status+0xc3/0xe40 drivers/block/loop.c:1235
#1: ffff888142392680 (&q->q_usage_counter(io)#18){++++}-{0:0}, at: blk_mq_freeze_queue include/linux/blk-mq.h:954 [inline]
#1: ffff888142392680 (&q->q_usage_counter(io)#18){++++}-{0:0}, at: loop_set_status+0x310/0xe40 drivers/block/loop.c:1251
#2: ffff8881423926b8 (&q->q_usage_counter(queue)#2){+.+.}-{0:0}, at: blk_mq_freeze_queue include/linux/blk-mq.h:954 [inline]
#2: ffff8881423926b8 (&q->q_usage_counter(queue)#2){+.+.}-{0:0}, at: loop_set_status+0x310/0xe40 drivers/block/loop.c:1251
4 locks held by syz.1.3370/18624:
#0: ffff88805aa42420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:499
#1: ffff88807863a0c0 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline]
#1: ffff88807863a0c0 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: vfs_setxattr+0x143/0x2e0 fs/xattr.c:320
#2: ffff8880785a2968 (&dquot->dq_lock){+.+.}-{4:4}, at: dquot_acquire+0x67/0x620 fs/quota/dquot.c:461
#3: ffff88805aa42208 (&s->s_dquot.dqio_sem){++++}-{4:4}, at: v2_read_dquot+0x50/0x1d0 fs/quota/quota_v2.c:342
3 locks held by syz.0.3371/18615:
#0: ffff8881423c8448 (&lo->lo_mutex){+.+.}-{4:4}, at: loop_set_status+0xc3/0xe40 drivers/block/loop.c:1235
#1: ffff888142391cf8 (&q->q_usage_counter(io)#17){++++}-{0:0}, at: blk_mq_freeze_queue include/linux/blk-mq.h:954 [inline]
#1: ffff888142391cf8 (&q->q_usage_counter(io)#17){++++}-{0:0}, at: loop_set_status+0x310/0xe40 drivers/block/loop.c:1251
#2: ffff888142391d30 (&q->q_usage_counter(queue)){+.+.}-{0:0}, at: blk_mq_freeze_queue include/linux/blk-mq.h:954 [inline]
#2: ffff888142391d30 (&q->q_usage_counter(queue)){+.+.}-{0:0}, at: loop_set_status+0x310/0xe40 drivers/block/loop.c:1251
4 locks held by syz.0.3371/18626:
#0: ffff88803381c420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:499
#1: ffff8880786920c0 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline]
#1: ffff8880786920c0 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: vfs_setxattr+0x143/0x2e0 fs/xattr.c:320
#2: ffff8880785a3ca8 (&dquot->dq_lock){+.+.}-{4:4}, at: dquot_acquire+0x67/0x620 fs/quota/dquot.c:461
#3: ffff88803381c208 (&s->s_dquot.dqio_sem){++++}-{4:4}, at: v2_read_dquot+0x50/0x1d0 fs/quota/quota_v2.c:342
3 locks held by syz.4.3374/18631:
#0: ffff8880247dc448 (&lo->lo_mutex){+.+.}-{4:4}, at: loop_set_status+0xc3/0xe40 drivers/block/loop.c:1235
#1: ffff888142394318 (&q->q_usage_counter(io)#21){++++}-{0:0}, at: blk_mq_freeze_queue include/linux/blk-mq.h:954 [inline]
#1: ffff888142394318 (&q->q_usage_counter(io)#21){++++}-{0:0}, at: loop_set_status+0x310/0xe40 drivers/block/loop.c:1251
#2: ffff888142394350 (&q->q_usage_counter(queue)#5){+.+.}-{0:0}, at: blk_mq_freeze_queue include/linux/blk-mq.h:954 [inline]
#2: ffff888142394350 (&q->q_usage_counter(queue)#5){+.+.}-{0:0}, at: loop_set_status+0x310/0xe40 drivers/block/loop.c:1251
4 locks held by syz.4.3374/18633:
#0: ffff88805e0e8420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:499
#1: ffff88807863e420 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline]
#1: ffff88807863e420 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: vfs_setxattr+0x143/0x2e0 fs/xattr.c:320
#2: ffff8880785a33e8 (&dquot->dq_lock){+.+.}-{4:4}, at: dquot_acquire+0x67/0x620 fs/quota/dquot.c:461
#3: ffff88805e0e8208 (&s->s_dquot.dqio_sem){++++}-{4:4}, at: v2_read_dquot+0x50/0x1d0 fs/quota/quota_v2.c:342
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 32 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xf90/0xfe0 kernel/hung_task.c:515
kthread+0x726/0x8b0 kernel/kthread.c:463
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 18624 Comm: syz.1.3370 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:400
Code: e8 ae ae 92 fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 4f fe fa fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 65 75 de fb cc 44 89 f9 80 e1 07
RSP: 0018:ffffc9000ce6ebf0 EFLAGS: 00000002
RAX: 1ffffffff3467000 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020
RBP: ffffffff9a338530 R08: ffff8881482f0237 R09: 1ffff1102905e046
R10: dffffc0000000000 R11: ffffffff8531cb20 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff9a3382a0 R15: 0000000000000000
FS: 00007fc4d59d56c0(0000) GS:ffff8881256f3000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0ae19e8600 CR3: 00000000527fe000 CR4: 0000000000350ef0
Call Trace:
<TASK>
serial_in drivers/tty/serial/8250/8250.h:128 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
wait_for_lsr+0x1a1/0x2f0 drivers/tty/serial/8250/8250_port.c:1961
fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3234 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3257 [inline]
serial8250_console_write+0x1348/0x1ba0 drivers/tty/serial/8250/8250_port.c:3342
console_emit_next_record kernel/printk/printk.c:3129 [inline]
console_flush_one_record kernel/printk/printk.c:3215 [inline]
console_flush_all+0x718/0xb20 kernel/printk/printk.c:3289
__console_flush_and_unlock kernel/printk/printk.c:3319 [inline]
console_unlock+0xd1/0x1c0 kernel/printk/printk.c:3359
vprintk_emit+0x485/0x560 kernel/printk/printk.c:2426
_printk+0xdd/0x130 kernel/printk/printk.c:2451
__quota_error+0x1a6/0x1d0 fs/quota/dquot.c:148
write_blk fs/quota/quota_tree.c:73 [inline]
get_free_dqblk+0x3cd/0x720 fs/quota/quota_tree.c:136
do_insert_tree+0x256/0x11d0 fs/quota/quota_tree.c:347
do_insert_tree+0x9d7/0x11d0 fs/quota/quota_tree.c:402
dq_insert_tree fs/quota/quota_tree.c:432 [inline]
qtree_write_dquot+0x4b1/0x5e0 fs/quota/quota_tree.c:451
v2_write_dquot+0x183/0x260 fs/quota/quota_v2.c:372
dquot_acquire+0x328/0x620 fs/quota/dquot.c:473
ext4_acquire_dquot+0x2e9/0x4c0 fs/ext4/super.c:6982
dqget+0x7b1/0xf10 fs/quota/dquot.c:980
__dquot_initialize+0x3ba/0xd30 fs/quota/dquot.c:1508
ext4_xattr_set+0xdb/0x340 fs/ext4/xattr.c:2543
__vfs_setxattr+0x43c/0x480 fs/xattr.c:200
__vfs_setxattr_noperm+0x12d/0x660 fs/xattr.c:234
vfs_setxattr+0x16a/0x2e0 fs/xattr.c:321
do_setxattr fs/xattr.c:636 [inline]
filename_setxattr+0x281/0x630 fs/xattr.c:665
path_setxattrat+0x3f3/0x430 fs/xattr.c:713
__do_sys_lsetxattr fs/xattr.c:754 [inline]
__se_sys_lsetxattr fs/xattr.c:750 [inline]
__x64_sys_lsetxattr+0xbf/0xe0 fs/xattr.c:750
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc4d639aeb9
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:00007fc4d59d5028 EFLAGS: 00000246 ORIG_RAX: 00000000000000bd
RAX: ffffffffffffffda RBX: 00007fc4d6616090 RCX: 00007fc4d639aeb9
RDX: 0000000000000000 RSI: 00002000000001c0 RDI: 0000200000000180
RBP: 00007fc4d6408c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc4d6616128 R14: 00007fc4d6616090 R15: 00007ffed7e83f48
</TASK>
---
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:
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If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want syzbot to run the reproducer, reply with:
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If you want to overwrite report's subsystems, reply with:
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^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [syzbot] [ext4?] INFO: task hung in block_read_full_folio (3)
2026-02-11 16:37 [syzbot] [ext4?] INFO: task hung in block_read_full_folio (3) syzbot
@ 2026-02-26 9:36 ` syzbot
0 siblings, 0 replies; 2+ messages in thread
From: syzbot @ 2026-02-26 9:36 UTC (permalink / raw)
To: adilger.kernel, linux-ext4, linux-kernel, syzkaller-bugs, tytso
syzbot has found a reproducer for the following issue on:
HEAD commit: d9d32e5bd5a4 Merge tag 'ata-7.0-rc2' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=105ac202580000
kernel config: https://syzkaller.appspot.com/x/.config?x=93740e6c6567fcec
dashboard link: https://syzkaller.appspot.com/bug?extid=03afbb29537f0336b7ad
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=151cc24a580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1218a8d6580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d223d806e90e/disk-d9d32e5b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d2d3e2c957ed/vmlinux-d9d32e5b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/db3a0620bab3/bzImage-d9d32e5b.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/0e3dce03880c/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=1450755a580000)
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+03afbb29537f0336b7ad@syzkaller.appspotmail.com
INFO: task udevd:5880 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D stack:24960 pid:5880 tgid:5880 ppid:5186 task_flags:0x400140 flags:0x00080000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x1585/0x5340 kernel/sched/core.c:6907
__schedule_loop kernel/sched/core.c:6989 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7004
io_schedule+0x7f/0xd0 kernel/sched/core.c:7831
bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:250
__wait_on_bit_lock+0xec/0x4e0 kernel/sched/wait_bit.c:93
out_of_line_wait_on_bit_lock+0x13b/0x190 kernel/sched/wait_bit.c:120
wait_on_bit_lock_io include/linux/wait_bit.h:221 [inline]
__lock_buffer fs/buffer.c:72 [inline]
lock_buffer include/linux/buffer_head.h:432 [inline]
block_read_full_folio+0x38f/0x830 fs/buffer.c:2436
filemap_read_folio+0x137/0x3b0 mm/filemap.c:2496
filemap_update_page mm/filemap.c:2583 [inline]
filemap_get_pages+0x1744/0x1f10 mm/filemap.c:2713
filemap_read+0x447/0x1230 mm/filemap.c:2800
blkdev_read_iter+0x30a/0x440 block/fops.c:855
new_sync_read fs/read_write.c:493 [inline]
vfs_read+0x582/0xa70 fs/read_write.c:574
ksys_read+0x150/0x270 fs/read_write.c:717
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f30023de407
RSP: 002b:00007ffef214d590 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f3002352880 RCX: 00007f30023de407
RDX: 0000000000000200 RSI: 00007f300234e000 RDI: 0000000000000009
RBP: 0000556fb2cd5c50 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000018
R13: 0000000000001000 R14: 0000556fb2ce78f8 R15: 00007f30025f739c
</TASK>
INFO: task syz.4.874:8117 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.874 state:D stack:25632 pid:8117 tgid:8117 ppid:5974 task_flags:0x400140 flags:0x00080002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x1585/0x5340 kernel/sched/core.c:6907
__schedule_loop kernel/sched/core.c:6989 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7004
io_schedule+0x7f/0xd0 kernel/sched/core.c:7831
folio_wait_bit_common+0x6d8/0xbc0 mm/filemap.c:1323
folio_lock include/linux/pagemap.h:1170 [inline]
__find_get_block_slow fs/buffer.c:206 [inline]
find_get_block_common+0x34f/0xe10 fs/buffer.c:1405
bdev_getblk+0x53/0x6e0 include/linux/gfp.h:-1
__getblk include/linux/buffer_head.h:380 [inline]
sb_getblk include/linux/buffer_head.h:386 [inline]
__ext4_get_inode_loc+0x7d8/0xfa0 fs/ext4/inode.c:4812
ext4_get_inode_loc fs/ext4/inode.c:4915 [inline]
ext4_reserve_inode_write+0x18b/0x360 fs/ext4/inode.c:6235
__ext4_mark_inode_dirty+0x14b/0x730 fs/ext4/inode.c:6413
__ext4_new_inode+0x3383/0x3d20 fs/ext4/ialloc.c:1333
ext4_mkdir+0x3da/0xbf0 fs/ext4/namei.c:3005
vfs_mkdir+0x413/0x630 fs/namei.c:5233
filename_mkdirat+0x285/0x510 fs/namei.c:5266
__do_sys_mkdir fs/namei.c:5293 [inline]
__se_sys_mkdir+0x34/0x150 fs/namei.c:5290
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f08d499c629
RSP: 002b:00007ffd2b703978 EFLAGS: 00000246 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 00007f08d4c15fa0 RCX: 00007f08d499c629
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000680
RBP: 00007f08d4a32b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f08d4c15fac R14: 00007f08d4c15fa0 R15: 00007f08d4c15fa0
</TASK>
Showing all locks held in the system:
3 locks held by kworker/u8:1/13:
#0: ffff88801fabd948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline]
#0: ffff88801fabd948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358
#1: ffffc90000127c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
#1: ffffc90000127c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358
#2: ffff88801b6f20e0 (&type->s_umount_key#41){.+.+}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:565
1 lock held by khungtaskd/32:
#0: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by kworker/u8:5/127:
#0: ffff8880b863ade0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x31/0x150 kernel/sched/core.c:647
#1: ffff8880b8624588 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880 kernel/sched/psi.c:933
1 lock held by udevd/5186:
2 locks held by getty/5573:
#0: ffff888032cfe0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000331e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211
2 locks held by udevd/5880:
#0: ffff888023452a28 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
#0: ffff888023452a28 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
#1: ffff888023452bc8 (mapping.invalidate_lock){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1093 [inline]
#1: ffff888023452bc8 (mapping.invalidate_lock){++++}-{4:4}, at: filemap_update_page mm/filemap.c:2549 [inline]
#1: ffff888023452bc8 (mapping.invalidate_lock){++++}-{4:4}, at: filemap_get_pages+0x991/0x1f10 mm/filemap.c:2713
1 lock held by syz-executor/5965:
#0: ffffffff8e766578 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#0: ffffffff8e766578 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961
1 lock held by syz-executor/5966:
4 locks held by udevd/6188:
2 locks held by syz.4.874/8117:
#0: ffff88807bcaa420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493
#1: ffff88805b1d03e0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline]
#1: ffff88805b1d03e0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2923 [inline]
#1: ffff88805b1d03e0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2934 [inline]
#1: ffff88805b1d03e0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_create+0x200/0x370 fs/namei.c:4922
2 locks held by udevd/8626:
#0: ffff888023451328 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
#0: ffff888023451328 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
#1: ffff8880b873ade0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x31/0x150 kernel/sched/core.c:647
1 lock held by udevd/8653:
1 lock held by udevd/8654:
#0: ffff888023454128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
#0: ffff888023454128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
2 locks held by syz.5.2965/13038:
1 lock held by syz.6.2966/13039:
1 lock held by syz.0.2964/13042:
1 lock held by kmmpd-loop0/13048:
#0: ffff8880b873ade0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x31/0x150 kernel/sched/core.c:647
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 32 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xfd9/0x1030 kernel/hung_task.c:515
kthread+0x388/0x470 kernel/kthread.c:467
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 6188 Comm: udevd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:srso_alias_safe_ret+0x0/0x7 arch/x86/lib/retpoline.S:210
Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc <48> 8d 64 24 08 c3 cc e8 f4 ff ff ff 0f 0b cc cc cc cc cc cc cc cc
RSP: 0018:ffffc90002ed73d0 EFLAGS: 00000293
RAX: ffffffff8ba52031 RBX: ffff888036ffd900 RCX: ffff88801ef73c80
RDX: 0000000000000000 RSI: 0000000000000300 RDI: 0000000000000300
RBP: 0000000000000001 R08: ffff88801ef73c80 R09: 0000000000000004
R10: 0000000000000003 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff8880760d8800 R14: ffff8880595dbdc0 R15: ffffffffffffffff
FS: 00007f3002352880(0000) GS:ffff888125564000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f300234d000 CR3: 000000002c631000 CR4: 0000000000350ef0
Call Trace:
<TASK>
srso_alias_return_thunk+0x5/0xfbef5 arch/x86/lib/retpoline.S:220
mt_locked lib/maple_tree.c:729 [inline]
mt_slot lib/maple_tree.c:736 [inline]
mas_next_slot+0x951/0xcf0 lib/maple_tree.c:4406
mas_find+0xb0e/0xd30 lib/maple_tree.c:5622
vma_next include/linux/mm.h:1323 [inline]
validate_mm+0xfe/0x4c0 mm/vma.c:650
mmap_region+0x1513/0x2240 mm/vma.c:2843
do_mmap+0xc39/0x10c0 mm/mmap.c:559
vm_mmap_pgoff+0x2c9/0x4f0 mm/util.c:581
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3002454822
Code: 00 00 00 0f 1f 44 00 00 41 f7 c1 ff 0f 00 00 75 27 55 89 cd 53 48 89 fb 48 85 ff 74 3b 41 89 ea 48 89 df b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 76 5b 5d c3 0f 1f 00 48 8b 05 a1 35 0d 00 64
RSP: 002b:00007ffef214d608 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3002454822
RDX: 0000000000000003 RSI: 0000000000000200 RDI: 0000000000000000
RBP: 0000000000000022 R08: 00000000ffffffff R09: 0000000000000000
R10: 0000000000000022 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000008000 R14: 0000556fb2cd30b0 R15: 0000000000004000
</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] 2+ messages in thread
end of thread, other threads:[~2026-02-26 9:36 UTC | newest]
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2026-02-11 16:37 [syzbot] [ext4?] INFO: task hung in block_read_full_folio (3) syzbot
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