[syzbot] [f2fs?] possible deadlock in f2fs_file_mmap

From: syzbot
Date: Sat Jun 17 2023 - 05:01:13 EST

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Hello,

syzbot found the following issue on:

HEAD commit: b16049b21162 Add linux-next specific files for 20230614
git tree: linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=134b968d280000
kernel config: https://syzkaller.appspot.com/x/.config?x=d103d5f9125e9fe9
dashboard link: https://syzkaller.appspot.com/bug?extid=c0e3db4f9cd6e05cadd3
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1620a663280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1327629b280000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a21dda01fc71/disk-b16049b2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f31e3fc32b7a/vmlinux-b16049b2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3967bcf93010/bzImage-b16049b2.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/8deff423ac75/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c0e3db4f9cd6e05cadd3@xxxxxxxxxxxxxxxxxxxxxxxxx

======================================================
WARNING: possible circular locking dependency detected
6.4.0-rc6-next-20230614-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor407/5033 is trying to acquire lock:
ffff888076c40a28 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:768 [inline]
ffff888076c40a28 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: f2fs_file_mmap+0x154/0x290 fs/f2fs/file.c:527

but task is already holding lock:
ffff8880787d3768 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:110 [inline]
ffff8880787d3768 (&mm->mmap_lock){++++}-{3:3}, at: vm_mmap_pgoff+0x158/0x3b0 mm/util.c:541

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&mm->mmap_lock){++++}-{3:3}:
down_read+0x9c/0x480 kernel/locking/rwsem.c:1520
mmap_read_lock include/linux/mmap_lock.h:142 [inline]
do_user_addr_fault+0xb3d/0x1210 arch/x86/mm/fault.c:1391
handle_page_fault arch/x86/mm/fault.c:1534 [inline]
exc_page_fault+0x98/0x170 arch/x86/mm/fault.c:1590
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570
fault_in_readable+0x129/0x210 mm/gup.c:1928
fault_in_iov_iter_readable+0x252/0x2c0 lib/iov_iter.c:216
f2fs_preallocate_blocks fs/f2fs/file.c:4508 [inline]
f2fs_file_write_iter+0x516/0x2500 fs/f2fs/file.c:4744
call_write_iter include/linux/fs.h:1865 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x960/0xd70 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

-> #0 (&sb->s_type->i_mutex_key#15){+.+.}-{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
down_write+0x92/0x200 kernel/locking/rwsem.c:1573
inode_lock include/linux/fs.h:768 [inline]
f2fs_file_mmap+0x154/0x290 fs/f2fs/file.c:527
call_mmap include/linux/fs.h:1870 [inline]
mmap_region+0x99c/0x2770 mm/mmap.c:2675
do_mmap+0x850/0xee0 mm/mmap.c:1367
vm_mmap_pgoff+0x1a2/0x3b0 mm/util.c:543
ksys_mmap_pgoff+0x42b/0x5b0 mm/mmap.c:1413
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:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&mm->mmap_lock);
lock(&sb->s_type->i_mutex_key#15);
lock(&mm->mmap_lock);
lock(&sb->s_type->i_mutex_key#15);

*** DEADLOCK ***

1 lock held by syz-executor407/5033:
#0: ffff8880787d3768 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:110 [inline]
#0: ffff8880787d3768 (&mm->mmap_lock){++++}-{3:3}, at: vm_mmap_pgoff+0x158/0x3b0 mm/util.c:541

stack backtrace:
CPU: 1 PID: 5033 Comm: syz-executor407 Not tainted 6.4.0-rc6-next-20230614-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
down_write+0x92/0x200 kernel/locking/rwsem.c:1573
inode_lock include/linux/fs.h:768 [inline]
f2fs_file_mmap+0x154/0x290 fs/f2fs/file.c:527
call_mmap include/linux/fs.h:1870 [inline]
mmap_region+0x99c/0x2770 mm/mmap.c:2675
do_mmap+0x850/0xee0 mm/mmap.c:1367
vm_mmap_pgoff+0x1a2/0x3b0 mm/util.c:543
ksys_mmap_pgoff+0x42b/0x5b0 mm/mmap.c:1413
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: 0033:0x7f5f44cdf4d9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 14 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:00007f5f3dc292f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f5f44d696f8 RCX: 00007f5f44cdf4d9
RDX: 000000000000000b RSI: 0000000000b36000 RDI: 0000000020000000
RBP: 00007f5f44d696f0 R08: 0000000000000004 R09: 0000000000000000
R10: 0000000000028011 R11: 0000000000000246 R12: 00007f5f44d696fc
R13: 656d6974797a616c R14: 746e657478656f6e R15: 0000000000022000
</TASK>

---
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Next message: Jisheng Zhang: "[PATCH] mmc: litex_mmc: set PROBE_PREFER_ASYNCHRONOUS"
Previous message: Liam Ni: "Re: [PATCH] mm/sparse:avoid null pointer access in memory_present()"
Next in thread: syzbot: "Re: [syzbot] [f2fs?] possible deadlock in f2fs_file_mmap"
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