syzbot

======================================================
WARNING: possible circular locking dependency detected
5.15.110-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor315/4122 is trying to acquire lock:
ffff88807c355528 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_read_lock+0x1c/0x50 include/linux/mmap_lock.h:117

but task is already holding lock:
ffff88806fcd00e0 (&sbi->s_lock){+.+.}-{3:3}, at: exfat_iterate+0x197/0x3290 fs/exfat/dir.c:229

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&sbi->s_lock){+.+.}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       exfat_get_block+0x1ca/0x22c0 fs/exfat/inode.c:303
       do_mpage_readpage+0x6c8/0x1f70 fs/mpage.c:231
       mpage_readahead+0x427/0x9b0 fs/mpage.c:389
       read_pages+0x159/0x8e0 mm/readahead.c:130
       page_cache_ra_unbounded+0x7b0/0x930 mm/readahead.c:239
       page_cache_sync_readahead include/linux/pagemap.h:833 [inline]
       filemap_get_pages mm/filemap.c:2551 [inline]
       filemap_read+0x71c/0x2980 mm/filemap.c:2634
       __kernel_read+0x5ac/0xa60 fs/read_write.c:443
       integrity_kernel_read+0xac/0xf0 security/integrity/iint.c:199
       ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:485 [inline]
       ima_calc_file_shash security/integrity/ima/ima_crypto.c:516 [inline]
       ima_calc_file_hash+0xa5d/0x1c00 security/integrity/ima/ima_crypto.c:573
       ima_collect_measurement+0x293/0x530 security/integrity/ima/ima_api.c:254
       process_measurement+0x1038/0x1d60 security/integrity/ima/ima_main.c:337
       ima_file_check+0xf3/0x180 security/integrity/ima/ima_main.c:519
       do_open fs/namei.c:3540 [inline]
       path_openat+0x2745/0x2f20 fs/namei.c:3672
       do_filp_open+0x21c/0x460 fs/namei.c:3699
       do_sys_openat2+0x13b/0x500 fs/open.c:1211
       do_sys_open fs/open.c:1227 [inline]
       __do_sys_openat fs/open.c:1243 [inline]
       __se_sys_openat fs/open.c:1238 [inline]
       __x64_sys_openat+0x243/0x290 fs/open.c:1238
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x61/0xcb

-> #1 (mapping.invalidate_lock#3){.+.+}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       down_read+0x3b/0x50 kernel/locking/rwsem.c:1488
       filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
       filemap_fault+0x708/0x1470 mm/filemap.c:3072
       __do_fault+0x139/0x340 mm/memory.c:3885
       do_read_fault mm/memory.c:4221 [inline]
       do_fault mm/memory.c:4349 [inline]
       handle_pte_fault mm/memory.c:4608 [inline]
       __handle_mm_fault mm/memory.c:4743 [inline]
       handle_mm_fault+0x376f/0x5950 mm/memory.c:4841
       do_user_addr_fault arch/x86/mm/fault.c:1397 [inline]
       handle_page_fault arch/x86/mm/fault.c:1485 [inline]
       exc_page_fault+0x271/0x740 arch/x86/mm/fault.c:1541
       asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:568
       strncpy_from_user+0x170/0x370 lib/strncpy_from_user.c:139
       getname_flags+0xf5/0x4e0 fs/namei.c:149
       do_sys_openat2+0xd2/0x500 fs/open.c:1205
       do_sys_open fs/open.c:1227 [inline]
       __do_sys_openat fs/open.c:1243 [inline]
       __se_sys_openat fs/open.c:1238 [inline]
       __x64_sys_openat+0x243/0x290 fs/open.c:1238
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x61/0xcb

-> #0 (&mm->mmap_lock#2){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain+0x1646/0x58b0 kernel/locking/lockdep.c:3787
       __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5011
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       down_read+0x3b/0x50 kernel/locking/rwsem.c:1488
       mmap_read_lock+0x1c/0x50 include/linux/mmap_lock.h:117
       do_user_addr_fault arch/x86/mm/fault.c:1348 [inline]
       handle_page_fault arch/x86/mm/fault.c:1485 [inline]
       exc_page_fault+0x5ce/0x740 arch/x86/mm/fault.c:1541
       asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:568
       user_access_begin arch/x86/include/asm/uaccess.h:574 [inline]
       filldir64+0x32b/0x730 fs/readdir.c:331
       dir_emit_dot include/linux/fs.h:3605 [inline]
       dir_emit_dots include/linux/fs.h:3616 [inline]
       exfat_iterate+0x2ef/0x3290 fs/exfat/dir.c:232
       iterate_dir+0x224/0x570
       __do_sys_getdents64 fs/readdir.c:369 [inline]
       __se_sys_getdents64+0x209/0x4f0 fs/readdir.c:354
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x61/0xcb

other info that might help us debug this:

Chain exists of:
  &mm->mmap_lock#2 --> mapping.invalidate_lock#3 --> &sbi->s_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&sbi->s_lock);
                               lock(mapping.invalidate_lock#3);
                               lock(&sbi->s_lock);
  lock(&mm->mmap_lock#2);

 *** DEADLOCK ***

3 locks held by syz-executor315/4122:
 #0: ffff888078ec8870 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x261/0x300 fs/file.c:1073
 #1: ffff888070a21cb0 (&sb->s_type->i_mutex_key#15){++++}-{3:3}, at: iterate_dir+0x131/0x570 fs/readdir.c:57
 #2: ffff88806fcd00e0 (&sbi->s_lock){+.+.}-{3:3}, at: exfat_iterate+0x197/0x3290 fs/exfat/dir.c:229

stack backtrace:
CPU: 1 PID: 4122 Comm: syz-executor315 Not tainted 5.15.110-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain+0x1646/0x58b0 kernel/locking/lockdep.c:3787
 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5011
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
 down_read+0x3b/0x50 kernel/locking/rwsem.c:1488
 mmap_read_lock+0x1c/0x50 include/linux/mmap_lock.h:117
 do_user_addr_fault arch/x86/mm/fault.c:1348 [inline]
 handle_page_fault arch/x86/mm/fault.c:1485 [inline]
 exc_page_fault+0x5ce/0x740 arch/x86/mm/fault.c:1541
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:568
RIP: 0010:filldir64+0x32b/0x730 fs/readdir.c:335
Code: fd 0f 82 60 02 00 00 48 b8 00 f0 ff ff ff 7f 00 00 48 39 c5 0f 87 4d 02 00 00 0f 01 cb 0f ae e8 48 8b 44 24 60 48 8b 4c 24 18 <48> 89 41 08 48 8b 44 24 10 48 8b 4c 24 58 48 89 08 48 8b 4c 24 20
RSP: 0018:ffffc90003bdf740 EFLAGS: 00050287
RAX: 0000000000000000 RBX: 0000000000000018 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000018 RDI: 00007ffffffff000
RBP: 0000000000000018 R08: ffffffff81d9d8ef R09: 0000000000000004
R10: 0000000000000003 R11: ffff88807a533a00 R12: ffffffff8a9e8a20
R13: ffffc90003bdfe70 R14: 0000000000000001 R15: 0000000000000000
 dir_emit_dot include/linux/fs.h:3605 [inline]
 dir_emit_dots include/linux/fs.h:3616 [inline]
 exfat_iterate+0x2ef/0x3290 fs/exfat/dir.c:232
 iterate_dir+0x224/0x570
 __do_sys_getdents64 fs/readdir.c:369 [inline]
 __se_sys_getdents64+0x209/0x4f0 fs/readdir.c:354
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fe4299f7739
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 18 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:00007fe42159a208 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007fe429a75798 RCX: 00007fe4299f7739
RDX: 0000000000008008 RSI: 0000000000000000 RDI: 0000000000000006
RBP: 00007fe429a75790 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe429a7579c
R13: 00007ffd02fe1a0f R14: 00007fe42159a300 R15: 0000000000022000
 </TASK>
----------------
Code disassembly (best guess):
   0:	fd                   	std
   1:	0f 82 60 02 00 00    	jb     0x267
   7:	48 b8 00 f0 ff ff ff 	movabs $0x7ffffffff000,%rax
   e:	7f 00 00
  11:	48 39 c5             	cmp    %rax,%rbp
  14:	0f 87 4d 02 00 00    	ja     0x267
  1a:	0f 01 cb             	stac
  1d:	0f ae e8             	lfence
  20:	48 8b 44 24 60       	mov    0x60(%rsp),%rax
  25:	48 8b 4c 24 18       	mov    0x18(%rsp),%rcx
* 2a:	48 89 41 08          	mov    %rax,0x8(%rcx) <-- trapping instruction
  2e:	48 8b 44 24 10       	mov    0x10(%rsp),%rax
  33:	48 8b 4c 24 58       	mov    0x58(%rsp),%rcx
  38:	48 89 08             	mov    %rcx,(%rax)
  3b:	48 8b 4c 24 20       	mov    0x20(%rsp),%rcx