Re: [syzbot] [mm?] possible deadlock in lock_mm_and_find_vma (2)

From: syzbot
Date: Thu Oct 03 2024 - 19:54:33 EST

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syzbot has found a reproducer for the following issue on:

HEAD commit: 7ec462100ef9 Merge tag 'pull-work.unaligned' of git://git...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=152ef580580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e3e4d87a80ed4297
dashboard link: https://syzkaller.appspot.com/bug?extid=b02bbe0ff80a09a08c1b
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1783d527980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15e9d3d0580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9c2b32151d7c/disk-7ec46210.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3c213e4aefaf/vmlinux-7ec46210.xz
kernel image: https://storage.googleapis.com/syzbot-assets/dba87bc205ec/bzImage-7ec46210.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b02bbe0ff80a09a08c1b@xxxxxxxxxxxxxxxxxxxxxxxxx

======================================================
WARNING: possible circular locking dependency detected
6.12.0-rc1-syzkaller-00046-g7ec462100ef9 #0 Not tainted
------------------------------------------------------
syz-executor224/5511 is trying to acquire lock:
ffff88802fabba98 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock_killable include/linux/mmap_lock.h:153 [inline]
ffff88802fabba98 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:6108 [inline]
ffff88802fabba98 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x3a9/0x6a0 mm/memory.c:6159

but task is already holding lock:
ffff88802ff17858 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:815 [inline]
ffff88802ff17858 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: shmem_file_write_iter+0x86/0x140 mm/shmem.c:3211

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}:
down_write+0x93/0x200 kernel/locking/rwsem.c:1577
inode_lock include/linux/fs.h:815 [inline]
process_measurement+0x39c/0x2370 security/integrity/ima/ima_main.c:250
ima_file_mmap+0x146/0x1d0 security/integrity/ima/ima_main.c:455
security_mmap_file+0x8bd/0x990 security/security.c:2977
__do_sys_remap_file_pages+0x526/0x900 mm/mmap.c:1692
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 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:3161 [inline]
check_prevs_add kernel/locking/lockdep.c:3280 [inline]
validate_chain kernel/locking/lockdep.c:3904 [inline]
__lock_acquire+0x250b/0x3ce0 kernel/locking/lockdep.c:5202
lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5825
down_read_killable+0x9d/0x380 kernel/locking/rwsem.c:1547
mmap_read_lock_killable include/linux/mmap_lock.h:153 [inline]
get_mmap_lock_carefully mm/memory.c:6108 [inline]
lock_mm_and_find_vma+0x3a9/0x6a0 mm/memory.c:6159
do_user_addr_fault+0x2b5/0x13f0 arch/x86/mm/fault.c:1361
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
fault_in_readable+0x126/0x230 mm/gup.c:2235
fault_in_iov_iter_readable+0x101/0x2c0 lib/iov_iter.c:94
generic_perform_write+0x21b/0x920 mm/filemap.c:4044
shmem_file_write_iter+0x10e/0x140 mm/shmem.c:3221
new_sync_write fs/read_write.c:590 [inline]
vfs_write+0x6b5/0x1140 fs/read_write.c:683
ksys_write+0x12f/0x260 fs/read_write.c:736
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 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#12);
lock(&mm->mmap_lock);
lock(&sb->s_type->i_mutex_key#12);
rlock(&mm->mmap_lock);

*** DEADLOCK ***

3 locks held by syz-executor224/5511:
#0: ffff888029a570b8 (&f->f_pos_lock){+.+.}-{3:3}, at: fdget_pos+0x24c/0x360 fs/file.c:1187
#1: ffff8880126a6420 (sb_writers#5){.+.+}-{0:0}, at: ksys_write+0x12f/0x260 fs/read_write.c:736
#2: ffff88802ff17858 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:815 [inline]
#2: ffff88802ff17858 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: shmem_file_write_iter+0x86/0x140 mm/shmem.c:3211

stack backtrace:
CPU: 1 UID: 0 PID: 5511 Comm: syz-executor224 Not tainted 6.12.0-rc1-syzkaller-00046-g7ec462100ef9 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_circular_bug+0x419/0x5d0 kernel/locking/lockdep.c:2074
check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2206
check_prev_add kernel/locking/lockdep.c:3161 [inline]
check_prevs_add kernel/locking/lockdep.c:3280 [inline]
validate_chain kernel/locking/lockdep.c:3904 [inline]
__lock_acquire+0x250b/0x3ce0 kernel/locking/lockdep.c:5202
lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5825
down_read_killable+0x9d/0x380 kernel/locking/rwsem.c:1547
mmap_read_lock_killable include/linux/mmap_lock.h:153 [inline]
get_mmap_lock_carefully mm/memory.c:6108 [inline]
lock_mm_and_find_vma+0x3a9/0x6a0 mm/memory.c:6159
do_user_addr_fault+0x2b5/0x13f0 arch/x86/mm/fault.c:1361
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0010:fault_in_readable+0x126/0x230 mm/gup.c:2235
Code: 38 ba ff 48 39 dd 0f 84 f0 00 00 00 45 31 f6 eb 11 e8 1e 38 ba ff 48 81 c3 00 10 00 00 48 39 eb 74 1d e8 0d 38 ba ff 45 89 f7 <8a> 03 31 ff 44 89 fe 88 44 24 28 e8 3a 3a ba ff 45 85 ff 74 d2 e8
RSP: 0018:ffffc90003bb7b18 EFLAGS: 00050293
RAX: 0000000000000000 RBX: 0000000000004000 RCX: ffffffff81d27776
RDX: ffff888011ecda00 RSI: ffffffff81d27763 RDI: 0000000000000005
RBP: 0000000000101000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000100082
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
fault_in_iov_iter_readable+0x101/0x2c0 lib/iov_iter.c:94
generic_perform_write+0x21b/0x920 mm/filemap.c:4044
shmem_file_write_iter+0x10e/0x140 mm/shmem.c:3221
new_sync_write fs/read_write.c:590 [inline]
vfs_write+0x6b5/0x1140 fs/read_write.c:683
ksys_write+0x12f/0x260 fs/read_write.c:736
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f04d812ac19
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 1c 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f04d80ba228 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f04d81b4198 RCX: 00007f04d812ac19
RDX: 0000000000100082 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007f04d81b4190 R08: 00007f04d80ba6c0 R09: 00007f04d80ba6c0
R10: 00007f04d80ba6c0 R11: 0000000000000246 R12: 00007f04d81b419c
R13: 00007f04d817a4ac R14: 0030656c69662f2e R15: 00007ffe59ac37d8
</TASK>
----------------
Code disassembly (best guess):
0: 38 ba ff 48 39 dd cmp %bh,-0x22c6b701(%rdx)
6: 0f 84 f0 00 00 00 je 0xfc
c: 45 31 f6 xor %r14d,%r14d
f: eb 11 jmp 0x22
11: e8 1e 38 ba ff call 0xffba3834
16: 48 81 c3 00 10 00 00 add $0x1000,%rbx
1d: 48 39 eb cmp %rbp,%rbx
20: 74 1d je 0x3f
22: e8 0d 38 ba ff call 0xffba3834
27: 45 89 f7 mov %r14d,%r15d
* 2a: 8a 03 mov (%rbx),%al <-- trapping instruction
2c: 31 ff xor %edi,%edi
2e: 44 89 fe mov %r15d,%esi
31: 88 44 24 28 mov %al,0x28(%rsp)
35: e8 3a 3a ba ff call 0xffba3a74
3a: 45 85 ff test %r15d,%r15d
3d: 74 d2 je 0x11
3f: e8 .byte 0xe8

---
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#syz test: git://repo/address.git branch-or-commit-hash
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Next message: Rosen Penev: "[PATCHv2 0/5] devicetree: move nvmem-cells users to nvmem-layout"
Previous message: Joe Damato: "Re: [RFC net-next v4 0/9] Add support for per-NAPI config via netlink"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]