syzbot

INFO: task syz.0.17:4320 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17        state:D stack:25712 pid: 4320 ppid:  4302 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
 wait_on_page_bit_common+0x815/0xe00 mm/filemap.c:1356
 lock_page include/linux/pagemap.h:625 [inline]
 pickup_page_for_submission fs/erofs/zdata.c:1135 [inline]
 z_erofs_submit_queue fs/erofs/zdata.c:1306 [inline]
 z_erofs_runqueue+0x6bf/0x1890 fs/erofs/zdata.c:1367
 z_erofs_readahead+0xb81/0x10c0 fs/erofs/zdata.c:1459
 read_pages+0x165/0x920 mm/readahead.c:130
 page_cache_ra_unbounded+0x830/0x930 mm/readahead.c:239
 do_page_cache_ra mm/readahead.c:269 [inline]
 force_page_cache_ra+0x3e5/0x440 mm/readahead.c:301
 force_page_cache_readahead mm/internal.h:78 [inline]
 generic_fadvise+0x520/0x7d0 mm/fadvise.c:107
 vfs_fadvise mm/fadvise.c:186 [inline]
 ksys_fadvise64_64 mm/fadvise.c:200 [inline]
 __do_sys_fadvise64 mm/fadvise.c:215 [inline]
 __se_sys_fadvise64 mm/fadvise.c:213 [inline]
 __x64_sys_fadvise64+0x139/0x180 mm/fadvise.c:213
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fd34c359ec9
RSP: 002b:00007ffdf377ff08 EFLAGS: 00000246
 ORIG_RAX: 00000000000000dd
RAX: ffffffffffffffda RBX: 00007fd34c5b0fa0 RCX: 00007fd34c359ec9
RDX: 0000000000000000 RSI: 0000000000e0ffff RDI: 0000000000000004
RBP: 00007fd34c3dcf91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd34c5b0fa0 R14: 00007fd34c5b0fa0 R15: 0000000000000004
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c11c660 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3945:
 #0: ffff88814cec2098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002d032e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
3 locks held by kworker/0:4/4214:
1 lock held by syz.0.17/4320:
 #0: ffff88805dd88320 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
 #0: ffff88805dd88320 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: page_cache_ra_unbounded+0x190/0x930 mm/readahead.c:195
1 lock held by syz.1.18/4342:
 #0: ffff88805dd88da0 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
 #0: ffff88805dd88da0 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: page_cache_ra_unbounded+0x190/0x930 mm/readahead.c:195
1 lock held by syz.2.19/4364:
 #0: ffff88805dd89820 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
 #0: ffff88805dd89820 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: page_cache_ra_unbounded+0x190/0x930 mm/readahead.c:195
1 lock held by syz.3.20/4392:
 #0: 
ffff88805dd8a2a0
 (
mapping.invalidate_lock
#3
){.+.+}-{3:3}
, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
, at: page_cache_ra_unbounded+0x190/0x930 mm/readahead.c:195
1 lock held by syz.4.21/4419:
 #0: 
ffff88805de74320
 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: page_cache_ra_unbounded+0x190/0x930 mm/readahead.c:195
1 lock held by syz.5.22/4446:
 #0: ffff88805dd8ad20 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
 #0: ffff88805dd8ad20 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: page_cache_ra_unbounded+0x190/0x930 mm/readahead.c:195
1 lock held by syz.6.23/4473:
 #0: ffff88805dd8b7a0 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
 #0: ffff88805dd8b7a0 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: page_cache_ra_unbounded+0x190/0x930 mm/readahead.c:195
1 lock held by syz.7.24/4506:
 #0: ffff88805de74da0 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
 #0: ffff88805de74da0 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: page_cache_ra_unbounded+0x190/0x930 mm/readahead.c:195
1 lock held by syz.8.25/4534:
 #0: ffff888053828320 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
 #0: ffff888053828320 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: page_cache_ra_unbounded+0x190/0x930 mm/readahead.c:195
4 locks held by syz.9.26/4560:

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe0f/0xe50 kernel/hung_task.c:369
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4560 Comm: syz.9.26 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:io_serial_out+0x78/0xb0 drivers/tty/serial/8250/8250_port.c:468
Code: 4e 32 fd 44 89 f9 d3 e5 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 a0 b6 76 fd 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d c3 44 89 f9 80 e1 07 38 c1 7c aa 4c 89 ff
RSP: 0018:ffffc90003c2f210 EFLAGS: 00000006
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 00000000000003f9 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 00000000000003f9 R08: 0000000000000004 R09: 0000000000000003
R10: fffff52000785e24 R11: 1ffff92000785e24 R12: dffffc0000000000
R13: ffffffff963ea7e0 R14: ffffffff963ea820 R15: 0000000000000000
FS:  000055558721a500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000005d2f7000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 serial_port_out include/linux/serial_core.h:349 [inline]
 serial8250_console_write+0x2b5/0xf80 drivers/tty/serial/8250/8250_port.c:-1
 call_console_drivers kernel/printk/printk.c:-1 [inline]
 console_unlock+0xc86/0x1200 kernel/printk/printk.c:2744
 vprintk_emit+0xc0/0x150 kernel/printk/printk.c:2274
 _printk+0xcc/0x110 kernel/printk/printk.c:2299
 _erofs_err+0x11f/0x170 fs/erofs/super.c:33
 z_erofs_readahead+0x8b0/0x10c0 fs/erofs/zdata.c:1451
 read_pages+0x165/0x920 mm/readahead.c:130
 page_cache_ra_unbounded+0x830/0x930 mm/readahead.c:239
 do_page_cache_ra mm/readahead.c:269 [inline]
 force_page_cache_ra+0x3e5/0x440 mm/readahead.c:301
 force_page_cache_readahead mm/internal.h:78 [inline]
 generic_fadvise+0x520/0x7d0 mm/fadvise.c:107
 vfs_fadvise mm/fadvise.c:186 [inline]
 ksys_fadvise64_64 mm/fadvise.c:200 [inline]
 __do_sys_fadvise64 mm/fadvise.c:215 [inline]
 __se_sys_fadvise64 mm/fadvise.c:213 [inline]
 __x64_sys_fadvise64+0x139/0x180 mm/fadvise.c:213
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f3d19f0cec9
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:00007ffd2b66f9f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000dd
RAX: ffffffffffffffda RBX: 00007f3d1a163fa0 RCX: 00007f3d19f0cec9
RDX: 0000000000000000 RSI: 0000000000e0ffff RDI: 0000000000000004
RBP: 00007f3d19f8ff91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3d1a163fa0 R14: 00007f3d1a163fa0 R15: 0000000000000004
 </TASK>