[syzbot] [mm?] possible deadlock in f2fs_file_write_iter

From: syzbot
Date: Mon Jun 26 2023 - 11:11:33 EST

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Hello,

syzbot found the following issue on:

HEAD commit: c87d46a9e8eb Add linux-next specific files for 20230622
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=129edf4b280000
kernel config: https://syzkaller.appspot.com/x/.config?x=d8ac8dd33677e8e0
dashboard link: https://syzkaller.appspot.com/bug?extid=b67b270114065129f12b
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bdf5ea2db527/disk-c87d46a9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3201e576e2ad/vmlinux-c87d46a9.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d011d9fa4e63/bzImage-c87d46a9.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b67b270114065129f12b@xxxxxxxxxxxxxxxxxxxxxxxxx

F2FS-fs (loop5): Mounted with checkpoint version = 48b305e5
======================================================
WARNING: possible circular locking dependency detected
6.4.0-rc7-next-20230622-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.5/16876 is trying to acquire lock:
ffff88802a033120 (&mm->mmap_lock){++++}-{3:3}, at: percpu_ref_put include/linux/percpu-refcount.h:351 [inline]
ffff88802a033120 (&mm->mmap_lock){++++}-{3:3}, at: put_dev_pagemap include/linux/memremap.h:251 [inline]
ffff88802a033120 (&mm->mmap_lock){++++}-{3:3}, at: gup_pte_range mm/gup.c:2583 [inline]
ffff88802a033120 (&mm->mmap_lock){++++}-{3:3}, at: gup_pmd_range mm/gup.c:2950 [inline]
ffff88802a033120 (&mm->mmap_lock){++++}-{3:3}, at: gup_pud_range mm/gup.c:2978 [inline]
ffff88802a033120 (&mm->mmap_lock){++++}-{3:3}, at: gup_p4d_range mm/gup.c:3003 [inline]
ffff88802a033120 (&mm->mmap_lock){++++}-{3:3}, at: gup_pgd_range mm/gup.c:3031 [inline]
ffff88802a033120 (&mm->mmap_lock){++++}-{3:3}, at: lockless_pages_from_mm mm/gup.c:3084 [inline]
ffff88802a033120 (&mm->mmap_lock){++++}-{3:3}, at: internal_get_user_pages_fast+0x135f/0x3370 mm/gup.c:3133

but task is already holding lock:
ffff88808b20ea30 (&fi->i_gc_rwsem[WRITE]){++++}-{3:3}, at: f2fs_down_read fs/f2fs/f2fs.h:2107 [inline]
ffff88808b20ea30 (&fi->i_gc_rwsem[WRITE]){++++}-{3:3}, at: f2fs_dio_write_iter fs/f2fs/file.c:4643 [inline]
ffff88808b20ea30 (&fi->i_gc_rwsem[WRITE]){++++}-{3:3}, at: f2fs_file_write_iter+0x1161/0x2500 fs/f2fs/file.c:4766

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 (&fi->i_gc_rwsem[WRITE]){++++}-{3:3}:
down_write+0x92/0x200 kernel/locking/rwsem.c:1573
f2fs_down_write fs/f2fs/f2fs.h:2132 [inline]
f2fs_setattr+0x50a/0x2090 fs/f2fs/file.c:1009
notify_change+0xb2c/0x1180 fs/attr.c:483
do_truncate+0x143/0x200 fs/open.c:66
do_sys_ftruncate+0x549/0x780 fs/open.c:194
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}:
down_write+0x92/0x200 kernel/locking/rwsem.c:1573
inode_lock include/linux/fs.h:771 [inline]
f2fs_file_mmap+0x154/0x290 fs/f2fs/file.c:527
call_mmap include/linux/fs.h:1876 [inline]
mmap_region+0x6cf/0x2570 mm/mmap.c:2669
do_mmap+0x837/0xea0 mm/mmap.c:1373
vm_mmap_pgoff+0x1a4/0x3b0 mm/util.c:543
ksys_mmap_pgoff+0x42b/0x5b0 mm/mmap.c:1419
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&mm->mmap_lock){++++}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3142 [inline]
check_prevs_add kernel/locking/lockdep.c:3261 [inline]
validate_chain kernel/locking/lockdep.c:3876 [inline]
__lock_acquire+0x2e9d/0x5e20 kernel/locking/lockdep.c:5144
lock_acquire.part.0+0x11c/0x370 kernel/locking/lockdep.c:5761
internal_get_user_pages_fast+0x13c0/0x3370 mm/gup.c:3122
pin_user_pages_fast+0xa8/0xf0 mm/gup.c:3246
iov_iter_extract_user_pages lib/iov_iter.c:1768 [inline]
iov_iter_extract_pages+0x293/0x18f0 lib/iov_iter.c:1831
__bio_iov_iter_get_pages block/bio.c:1276 [inline]
bio_iov_iter_get_pages block/bio.c:1349 [inline]
bio_iov_iter_get_pages+0x33b/0xd50 block/bio.c:1336
iomap_dio_bio_iter+0x82a/0x1430 fs/iomap/direct-io.c:317
iomap_dio_iter fs/iomap/direct-io.c:430 [inline]
__iomap_dio_rw+0x1010/0x1d80 fs/iomap/direct-io.c:575
f2fs_dio_write_iter fs/f2fs/file.c:4657 [inline]
f2fs_file_write_iter+0x121b/0x2500 fs/f2fs/file.c:4766
call_write_iter include/linux/fs.h:1871 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x981/0xda0 fs/read_write.c:584
ksys_write+0x122/0x250 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Chain exists of:
&mm->mmap_lock --> &sb->s_type->i_mutex_key#21 --> &fi->i_gc_rwsem[WRITE]

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
rlock(&fi->i_gc_rwsem[WRITE]);
lock(&sb->s_type->i_mutex_key#21);
lock(&fi->i_gc_rwsem[WRITE]);
rlock(&mm->mmap_lock);

*** DEADLOCK ***

4 locks held by syz-executor.5/16876:
#0: ffff888023d4f9c8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xd7/0xf0 fs/file.c:1047
#1: ffff8880846ac410 (sb_writers#14){.+.+}-{0:0}, at: ksys_write+0x122/0x250 fs/read_write.c:637
#2: ffff88808b20e450 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:771 [inline]
#2: ffff88808b20e450 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: f2fs_file_write_iter+0x297/0x2500 fs/f2fs/file.c:4744
#3: ffff88808b20ea30 (&fi->i_gc_rwsem[WRITE]){++++}-{3:3}, at: f2fs_down_read fs/f2fs/f2fs.h:2107 [inline]
#3: ffff88808b20ea30 (&fi->i_gc_rwsem[WRITE]){++++}-{3:3}, at: f2fs_dio_write_iter fs/f2fs/file.c:4643 [inline]
#3: ffff88808b20ea30 (&fi->i_gc_rwsem[WRITE]){++++}-{3:3}, at: f2fs_file_write_iter+0x1161/0x2500 fs/f2fs/file.c:4766

stack backtrace:
CPU: 0 PID: 16876 Comm: syz-executor.5 Not tainted 6.4.0-rc7-next-20230622-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
check_noncircular+0x2df/0x3b0 kernel/locking/lockdep.c:2195
check_prev_add kernel/locking/lockdep.c:3142 [inline]
check_prevs_add kernel/locking/lockdep.c:3261 [inline]
validate_chain kernel/locking/lockdep.c:3876 [inline]
__lock_acquire+0x2e9d/0x5e20 kernel/locking/lockdep.c:5144
lock_acquire.part.0+0x11c/0x370 kernel/locking/lockdep.c:5761
internal_get_user_pages_fast+0x13c0/0x3370 mm/gup.c:3122
pin_user_pages_fast+0xa8/0xf0 mm/gup.c:3246
iov_iter_extract_user_pages lib/iov_iter.c:1768 [inline]
iov_iter_extract_pages+0x293/0x18f0 lib/iov_iter.c:1831
__bio_iov_iter_get_pages block/bio.c:1276 [inline]
bio_iov_iter_get_pages block/bio.c:1349 [inline]
bio_iov_iter_get_pages+0x33b/0xd50 block/bio.c:1336
iomap_dio_bio_iter+0x82a/0x1430 fs/iomap/direct-io.c:317
iomap_dio_iter fs/iomap/direct-io.c:430 [inline]
__iomap_dio_rw+0x1010/0x1d80 fs/iomap/direct-io.c:575
f2fs_dio_write_iter fs/f2fs/file.c:4657 [inline]
f2fs_file_write_iter+0x121b/0x2500 fs/f2fs/file.c:4766
call_write_iter include/linux/fs.h:1871 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x981/0xda0 fs/read_write.c:584
ksys_write+0x122/0x250 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f8e4728c389
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8e4800f168 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f8e473abf80 RCX: 00007f8e4728c389
RDX: 000000000002a000 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00007f8e472d7493 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff9aab699f R14: 00007f8e4800f300 R15: 0000000000022000
</TASK>

---
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Next message: Ahelenia Ziemiańska: "Re: splice(-> FIFO) never wakes up inotify IN_MODIFY?"
Previous message: Lorenz Bauer: "[PATCH bpf-next v3 6/7] bpf, net: Support SO_REUSEPORT sockets with bpf_sk_assign"
Next in thread: Eric Biggers: "Re: [syzbot] [mm?] possible deadlock in f2fs_file_write_iter"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]