[syzbot] possible deadlock in __f2fs_ioctl

From: syzbot
Date: Fri Dec 09 2022 - 04:08:47 EST

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Hello,

syzbot found the following issue on:

HEAD commit: a5541c0811a0 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=13a6e7cb880000
kernel config: https://syzkaller.appspot.com/x/.config?x=cbd4e584773e9397
dashboard link: https://syzkaller.appspot.com/bug?extid=4793f6096d174c90b4f7
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4b7702208fb9/disk-a5541c08.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9ec0153ec051/vmlinux-a5541c08.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6f8725ad290a/Image-a5541c08.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4793f6096d174c90b4f7@xxxxxxxxxxxxxxxxxxxxxxxxx

F2FS-fs (loop2): invalid crc value
F2FS-fs (loop2): Found nat_bits in checkpoint
F2FS-fs (loop2): Mounted with checkpoint version = 48b305e4
======================================================
WARNING: possible circular locking dependency detected
6.1.0-rc8-syzkaller-33330-ga5541c0811a0 #0 Not tainted
------------------------------------------------------
syz-executor.2/32123 is trying to acquire lock:
ffff0000c0e1a608 (&mm->mmap_lock){++++}-{3:3}, at: __might_fault+0x54/0xb4 mm/memory.c:5644

but task is already holding lock:
ffff0001317c6088 (&sbi->sb_lock){++++}-{3:3}, at: f2fs_down_write fs/f2fs/f2fs.h:2205 [inline]
ffff0001317c6088 (&sbi->sb_lock){++++}-{3:3}, at: f2fs_ioc_get_encryption_pwsalt fs/f2fs/file.c:2334 [inline]
ffff0001317c6088 (&sbi->sb_lock){++++}-{3:3}, at: __f2fs_ioctl+0x1370/0x3318 fs/f2fs/file.c:4151

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #3 (&sbi->sb_lock){++++}-{3:3}:
down_write+0x5c/0x88 kernel/locking/rwsem.c:1562
f2fs_down_write fs/f2fs/f2fs.h:2205 [inline]
f2fs_handle_error+0x9c/0x17c fs/f2fs/super.c:3898
f2fs_check_nid_range fs/f2fs/node.c:39 [inline]
add_free_nid+0x4d8/0x50c fs/f2fs/node.c:2282
scan_nat_page fs/f2fs/node.c:2384 [inline]
__f2fs_build_free_nids fs/f2fs/node.c:2490 [inline]
f2fs_build_free_nids+0x680/0x8f4 fs/f2fs/node.c:2528
f2fs_build_node_manager+0x624/0x64c fs/f2fs/node.c:3313
f2fs_fill_super+0x1470/0x1e90 fs/f2fs/super.c:4306
mount_bdev+0x1b8/0x210 fs/super.c:1401
f2fs_mount+0x44/0x58 fs/f2fs/super.c:4580
legacy_get_tree+0x30/0x74 fs/fs_context.c:610
vfs_get_tree+0x40/0x140 fs/super.c:1531
do_new_mount+0x1dc/0x4e4 fs/namespace.c:3040
path_mount+0x358/0x890 fs/namespace.c:3370
do_mount fs/namespace.c:3383 [inline]
__do_sys_mount fs/namespace.c:3591 [inline]
__se_sys_mount fs/namespace.c:3568 [inline]
__arm64_sys_mount+0x2c4/0x3c4 fs/namespace.c:3568
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x48/0x140 arch/arm64/kernel/syscall.c:197
el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584

-> #2 (&nm_i->nat_tree_lock){++++}-{3:3}:
down_read+0x5c/0x78 kernel/locking/rwsem.c:1509
f2fs_down_read fs/f2fs/f2fs.h:2180 [inline]
f2fs_get_node_info+0x74/0x458 fs/f2fs/node.c:560
read_node_page+0x100/0x7a4 fs/f2fs/node.c:1358
__get_node_page+0x1b4/0xa3c fs/f2fs/node.c:1419
f2fs_get_node_page fs/f2fs/node.c:1468 [inline]
f2fs_get_dnode_of_data+0xc8/0xad0 fs/f2fs/node.c:776
f2fs_remove_inode_page+0x50/0x288 fs/f2fs/node.c:1225
f2fs_evict_inode+0x348/0x978 fs/f2fs/inode.c:813
evict+0xec/0x334 fs/inode.c:664
iput_final fs/inode.c:1747 [inline]
iput+0x2c4/0x324 fs/inode.c:1773
f2fs_new_inode+0x284/0x7bc fs/f2fs/namei.c:152
f2fs_create+0xa4/0x4b0 fs/f2fs/namei.c:355
lookup_open fs/namei.c:3413 [inline]
open_last_lookups fs/namei.c:3481 [inline]
path_openat+0x804/0x11c4 fs/namei.c:3711
do_filp_open+0xdc/0x1b8 fs/namei.c:3741
do_sys_openat2+0xb8/0x22c fs/open.c:1310
do_sys_open fs/open.c:1326 [inline]
__do_sys_openat fs/open.c:1342 [inline]
__se_sys_openat fs/open.c:1337 [inline]
__arm64_sys_openat+0xb0/0xe0 fs/open.c:1337
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x48/0x140 arch/arm64/kernel/syscall.c:197
el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584

-> #1 (&sbi->cp_rwsem){++++}-{3:3}:
down_read+0x5c/0x78 kernel/locking/rwsem.c:1509
f2fs_down_read fs/f2fs/f2fs.h:2180 [inline]
f2fs_lock_op fs/f2fs/f2fs.h:2223 [inline]
f2fs_convert_inline_inode+0x1e8/0x2e4 fs/f2fs/inline.c:219
f2fs_vm_page_mkwrite+0xb4/0x9a4 fs/f2fs/file.c:79
do_page_mkwrite+0x74/0x288 mm/memory.c:2977
wp_page_shared+0x8c/0x364 mm/memory.c:3323
do_wp_page+0x794/0xd10 mm/memory.c:3473
handle_pte_fault mm/memory.c:4972 [inline]
__handle_mm_fault mm/memory.c:5096 [inline]
handle_mm_fault+0x880/0xa48 mm/memory.c:5217
__do_page_fault arch/arm64/mm/fault.c:508 [inline]
do_page_fault+0x428/0x79c arch/arm64/mm/fault.c:608
do_mem_abort+0x54/0x130 arch/arm64/mm/fault.c:827
el0_da+0x70/0x16c arch/arm64/kernel/entry-common.c:515
el0t_64_sync_handler+0xcc/0xf0 arch/arm64/kernel/entry-common.c:658
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584

-> #0 (&mm->mmap_lock){++++}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3097 [inline]
check_prevs_add kernel/locking/lockdep.c:3216 [inline]
validate_chain kernel/locking/lockdep.c:3831 [inline]
__lock_acquire+0x1530/0x3084 kernel/locking/lockdep.c:5055
lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5668
__might_fault+0x7c/0xb4 mm/memory.c:5645
_copy_to_user include/linux/uaccess.h:143 [inline]
copy_to_user include/linux/uaccess.h:169 [inline]
f2fs_ioc_get_encryption_pwsalt fs/f2fs/file.c:2349 [inline]
__f2fs_ioctl+0x3204/0x3318 fs/f2fs/file.c:4151
f2fs_ioctl+0x74/0xbc fs/f2fs/file.c:4224
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__arm64_sys_ioctl+0xd0/0x140 fs/ioctl.c:856
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x48/0x140 arch/arm64/kernel/syscall.c:197
el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584

other info that might help us debug this:

Chain exists of:
&mm->mmap_lock --> &nm_i->nat_tree_lock --> &sbi->sb_lock

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&sbi->sb_lock);
lock(&nm_i->nat_tree_lock);
lock(&sbi->sb_lock);
lock(&mm->mmap_lock);

*** DEADLOCK ***

2 locks held by syz-executor.2/32123:
#0: ffff000112968460 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write_file+0x28/0xd8 fs/namespace.c:437
#1: ffff0001317c6088 (&sbi->sb_lock){++++}-{3:3}, at: f2fs_down_write fs/f2fs/f2fs.h:2205 [inline]
#1: ffff0001317c6088 (&sbi->sb_lock){++++}-{3:3}, at: f2fs_ioc_get_encryption_pwsalt fs/f2fs/file.c:2334 [inline]
#1: ffff0001317c6088 (&sbi->sb_lock){++++}-{3:3}, at: __f2fs_ioctl+0x1370/0x3318 fs/f2fs/file.c:4151

stack backtrace:
CPU: 1 PID: 32123 Comm: syz-executor.2 Not tainted 6.1.0-rc8-syzkaller-33330-ga5541c0811a0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/30/2022
Call trace:
dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:156
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:163
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x104/0x16c lib/dump_stack.c:106
dump_stack+0x1c/0x58 lib/dump_stack.c:113
print_circular_bug+0x2c4/0x2c8 kernel/locking/lockdep.c:2055
check_noncircular+0x14c/0x154 kernel/locking/lockdep.c:2177
check_prev_add kernel/locking/lockdep.c:3097 [inline]
check_prevs_add kernel/locking/lockdep.c:3216 [inline]
validate_chain kernel/locking/lockdep.c:3831 [inline]
__lock_acquire+0x1530/0x3084 kernel/locking/lockdep.c:5055
lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5668
__might_fault+0x7c/0xb4 mm/memory.c:5645
_copy_to_user include/linux/uaccess.h:143 [inline]
copy_to_user include/linux/uaccess.h:169 [inline]
f2fs_ioc_get_encryption_pwsalt fs/f2fs/file.c:2349 [inline]
__f2fs_ioctl+0x3204/0x3318 fs/f2fs/file.c:4151
f2fs_ioctl+0x74/0xbc fs/f2fs/file.c:4224
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__arm64_sys_ioctl+0xd0/0x140 fs/ioctl.c:856
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x48/0x140 arch/arm64/kernel/syscall.c:197
el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584

---
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