linux-kernel - Re: [syzbot] [erofs?] INFO: task hung in z_erofs

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Message-ID: <0000000000006d2b8f06204e76f8@google.com>
Date: Thu, 22 Aug 2024 17:00:26 -0700
From: syzbot <syzbot+4fc98ed414ae63d1ada2@...kaller.appspotmail.com>
To: chao@...nel.org, dhavale@...gle.com, hsiangkao@...ux.alibaba.com, 
	huyue2@...lpad.com, jefflexu@...ux.alibaba.com, linux-erofs@...ts.ozlabs.org, 
	linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com, 
	xiang@...nel.org
Subject: Re: [syzbot] [erofs?] INFO: task hung in z_erofs_runqueue

syzbot has found a reproducer for the following issue on:

HEAD commit:    048499f92ed7 Merge branch 'for-next/core' into for-kernelci
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=1118b433980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5c686716759500c2
dashboard link: https://syzkaller.appspot.com/bug?extid=4fc98ed414ae63d1ada2
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10d09f83980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10e3247b980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/66c48334a6dc/disk-048499f9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a8e45cac172b/vmlinux-048499f9.xz
kernel image: https://storage.googleapis.com/syzbot-assets/80940291bc58/Image-048499f9.gz.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/f7747709ae10/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4fc98ed414ae63d1ada2@...kaller.appspotmail.com

INFO: task syz-executor173:6412 blocked for more than 143 seconds.
      Not tainted 6.11.0-rc4-syzkaller-g048499f92ed7 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor173 state:D stack:0     pid:6412  tgid:6412  ppid:6411   flags:0x00000005
Call trace:
 __switch_to+0x314/0x560 arch/arm64/kernel/process.c:553
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x13d4/0x2418 kernel/sched/core.c:6529
 __schedule_loop kernel/sched/core.c:6606 [inline]
 schedule+0xbc/0x238 kernel/sched/core.c:6621
 io_schedule+0x8c/0x124 kernel/sched/core.c:7401
 folio_wait_bit_common+0x65c/0xb90 mm/filemap.c:1307
 __folio_lock+0x2c/0x3c mm/filemap.c:1645
 folio_lock include/linux/pagemap.h:1050 [inline]
 z_erofs_fill_bio_vec fs/erofs/zdata.c:1470 [inline]
 z_erofs_submit_queue fs/erofs/zdata.c:1650 [inline]
 z_erofs_runqueue+0x838/0x17ec fs/erofs/zdata.c:1732
 z_erofs_readahead+0x858/0xc18 fs/erofs/zdata.c:1863
 read_pages+0x160/0x694 mm/readahead.c:160
 page_cache_ra_unbounded+0x484/0x584 mm/readahead.c:273
 do_page_cache_ra mm/readahead.c:303 [inline]
 force_page_cache_ra+0x22c/0x290 mm/readahead.c:332
 force_page_cache_readahead mm/internal.h:338 [inline]
 generic_fadvise+0x3e8/0x6a0 mm/fadvise.c:106
 vfs_fadvise mm/fadvise.c:185 [inline]
 ksys_fadvise64_64 mm/fadvise.c:199 [inline]
 __do_sys_fadvise64_64 mm/fadvise.c:207 [inline]
 __se_sys_fadvise64_64 mm/fadvise.c:205 [inline]
 __arm64_sys_fadvise64_64+0x12c/0x174 mm/fadvise.c:205
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712
 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffff80008f6edb60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:325
2 locks held by getty/6155:
 #0: ffff0000d23b60a0 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80009836e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41c/0x1228 drivers/tty/n_tty.c:2211
1 lock held by syz-executor173/6412:
 #0: ffff0000deee0330 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:854 [inline]
 #0: ffff0000deee0330 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: page_cache_ra_unbounded+0xc8/0x584 mm/readahead.c:225

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



---
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#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.