Re: [syzbot] [mm?] possible deadlock in gup_fast_fallback

From: syzbot
Date: Wed Jul 24 2024 - 10:10:46 EST

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syzbot has found a reproducer for the following issue on:

HEAD commit: 786c8248dbd3 Merge tag 'perf-tools-fixes-for-v6.11-2024-07..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=15009665980000
kernel config: https://syzkaller.appspot.com/x/.config?x=d732ba79a3d0331b
dashboard link: https://syzkaller.appspot.com/bug?extid=63ba90b81c16b86379bd
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=162862e3980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10d14ce3980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a022c722f874/disk-786c8248.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/860e2faa9749/vmlinux-786c8248.xz
kernel image: https://storage.googleapis.com/syzbot-assets/518e4afe4ede/bzImage-786c8248.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/09d1622c5e09/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+63ba90b81c16b86379bd@xxxxxxxxxxxxxxxxxxxxxxxxx

ntfs3: loop0: Mark volume as dirty due to NTFS errors
ntfs3: loop0: Failed to load $Extend (-116).
ntfs3: loop0: Failed to initialize $Extend.
======================================================
WARNING: possible circular locking dependency detected
6.10.0-syzkaller-12246-g786c8248dbd3 #0 Not tainted
------------------------------------------------------
syz-executor288/5099 is trying to acquire lock:
ffff888063210b18 (&mm->mmap_lock){++++}-{3:3}, at: gup_fast_fallback+0x233/0x2b50 mm/gup.c:3367

but task is already holding lock:
ffff88807a2be310 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: inode_trylock include/linux/fs.h:819 [inline]
ffff88807a2be310 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: ntfs_file_write_iter+0x24a/0x740 fs/ntfs3/file.c:1166

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
down_write+0x99/0x220 kernel/locking/rwsem.c:1579
inode_lock include/linux/fs.h:799 [inline]
ntfs_file_mmap+0x5bf/0x850 fs/ntfs3/file.c:368
call_mmap include/linux/fs.h:2129 [inline]
mmap_region+0xe8f/0x2090 mm/mmap.c:2927
do_mmap+0x8ad/0xfa0 mm/mmap.c:1438
vm_mmap_pgoff+0x1dd/0x3d0 mm/util.c:588
ksys_mmap_pgoff+0x4f1/0x720 mm/mmap.c:1484
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&mm->mmap_lock){++++}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3133 [inline]
check_prevs_add kernel/locking/lockdep.c:3252 [inline]
validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3868
__lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
gup_fast_fallback+0x24c/0x2b50 mm/gup.c:3367
pin_user_pages_fast+0xcc/0x160 mm/gup.c:3491
iov_iter_extract_user_pages lib/iov_iter.c:1583 [inline]
iov_iter_extract_pages+0x3db/0x720 lib/iov_iter.c:1646
dio_refill_pages fs/direct-io.c:173 [inline]
dio_get_page fs/direct-io.c:214 [inline]
do_direct_IO fs/direct-io.c:916 [inline]
__blockdev_direct_IO+0x144c/0x4890 fs/direct-io.c:1249
blockdev_direct_IO include/linux/fs.h:3212 [inline]
ntfs_direct_IO+0x195/0x370 fs/ntfs3/inode.c:801
generic_file_direct_write+0x130/0x350 mm/filemap.c:3941
__generic_file_write_iter+0x129/0x230 mm/filemap.c:4107
ntfs_file_write_iter+0x663/0x740 fs/ntfs3/file.c:1193
do_iter_readv_writev+0x60a/0x890
vfs_writev+0x37c/0xbb0 fs/read_write.c:971
do_pwritev fs/read_write.c:1072 [inline]
__do_sys_pwritev2 fs/read_write.c:1131 [inline]
__se_sys_pwritev2+0x1ca/0x2d0 fs/read_write.c:1122
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&sb->s_type->i_mutex_key#14);
lock(&mm->mmap_lock);
lock(&sb->s_type->i_mutex_key#14);
rlock(&mm->mmap_lock);

*** DEADLOCK ***

2 locks held by syz-executor288/5099:
#0: ffff888023990420 (sb_writers#9){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2876 [inline]
#0: ffff888023990420 (sb_writers#9){.+.+}-{0:0}, at: vfs_writev+0x2d4/0xbb0 fs/read_write.c:969
#1: ffff88807a2be310 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: inode_trylock include/linux/fs.h:819 [inline]
#1: ffff88807a2be310 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: ntfs_file_write_iter+0x24a/0x740 fs/ntfs3/file.c:1166

stack backtrace:
CPU: 0 UID: 0 PID: 5099 Comm: syz-executor288 Not tainted 6.10.0-syzkaller-12246-g786c8248dbd3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:93 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2186
check_prev_add kernel/locking/lockdep.c:3133 [inline]
check_prevs_add kernel/locking/lockdep.c:3252 [inline]
validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3868
__lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
gup_fast_fallback+0x24c/0x2b50 mm/gup.c:3367
pin_user_pages_fast+0xcc/0x160 mm/gup.c:3491
iov_iter_extract_user_pages lib/iov_iter.c:1583 [inline]
iov_iter_extract_pages+0x3db/0x720 lib/iov_iter.c:1646
dio_refill_pages fs/direct-io.c:173 [inline]
dio_get_page fs/direct-io.c:214 [inline]
do_direct_IO fs/direct-io.c:916 [inline]
__blockdev_direct_IO+0x144c/0x4890 fs/direct-io.c:1249
blockdev_direct_IO include/linux/fs.h:3212 [inline]
ntfs_direct_IO+0x195/0x370 fs/ntfs3/inode.c:801
generic_file_direct_write+0x130/0x350 mm/filemap.c:3941
__generic_file_write_iter+0x129/0x230 mm/filemap.c:4107
ntfs_file_write_iter+0x663/0x740 fs/ntfs3/file.c:1193
do_iter_readv_writev+0x60a/0x890
vfs_writev+0x37c/0xbb0 fs/read_write.c:971
do_pwritev fs/read_write.c:1072 [inline]
__do_sys_pwritev2 fs/read_write.c:1131 [inline]
__se_sys_pwritev2+0x1ca/0x2d0 fs/read_write.c:1122
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb9777dcb59
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 17 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:00007ffe15926128 EFLAGS: 00000246 ORIG_RAX: 0000000000000148
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb9777dcb59
RDX: 0000000000000001 RSI: 0000000020000240 RDI: 0000000000000005
RBP: 00007fb97786f5f0 R08: 0000000000000000 R09: 0000000000000003
R10: 0000000000007000 R11: 0000000000000246 R12: 00007ffe15926160
R13: 00007ffe15926388 R14: 431bde82d7b634db R15: 00007fb97782503b
</TASK>

---
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#syz test: git://repo/address.git branch-or-commit-hash
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Next message: Alan Stern: "Re: [PATCH] USB: core: hub_port_reset: Remove extra 40 ms reset recovery time"
Previous message: Manivannan Sadhasivam: "Re: [PATCH v3 2/2] PCI: qcom: Avoid DBI and ATU register space mirror to BAR/MMIO region"
Next in thread: syzbot: "Re: [syzbot] [mm?] possible deadlock in gup_fast_fallback"
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