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Date:   Tue, 18 Jul 2023 02:52:46 -0700
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Subject: [syzbot] [mm?] possible deadlock in shmem_uncharge (2)
From:   syzbot <syzbot+38ca19393fb3344f57e6@syzkaller.appspotmail.com>
To:     akpm@linux-foundation.org, cem@kernel.org, cmaiolino@redhat.com,
        hughd@google.com, jack@suse.cz, lczerner@redhat.com,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        syzkaller-bugs@googlegroups.com
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Hello,

syzbot found the following issue on:

HEAD commit:    7c2878be5732 Add linux-next specific files for 20230714
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=14b77fd8a80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3baff2936ac3cefa
dashboard link: https://syzkaller.appspot.com/bug?extid=38ca19393fb3344f57e6
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=153eea12a80000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1169adeca80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bfdfa043f096/disk-7c2878be.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/cf7a97f69e2a/vmlinux-7c2878be.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8366b63af2c6/bzImage-7c2878be.xz

The issue was bisected to:

commit 1a93dd24f1bee98ca121e68ce5c0de4a60a0a0b6
Author: Carlos Maiolino <cem@kernel.org>
Date:   Thu Jul 13 13:48:47 2023 +0000

    shmem: quota support

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=11af3afaa80000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=13af3afaa80000
console output: https://syzkaller.appspot.com/x/log.txt?x=15af3afaa80000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+38ca19393fb3344f57e6@syzkaller.appspotmail.com
Fixes: 1a93dd24f1be ("shmem: quota support")

======================================================
WARNING: possible circular locking dependency detected
6.5.0-rc1-next-20230714-syzkaller #0 Not tainted
------------------------------------------------------
/5027 is trying to acquire lock:
ffff88807dbd8758 (&info->lock){....}-{2:2}, at: shmem_uncharge+0x28/0x2b0 mm/shmem.c:450

but task is already holding lock:
ffff88801526c068 (&lruvec->lru_lock){....}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
ffff88801526c068 (&lruvec->lru_lock){....}-{2:2}, at: folio_lruvec_lock+0x1ba/0x3b0 mm/memcontrol.c:1323

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&lruvec->lru_lock){....}-{2:2}:
       __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
       _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
       spin_lock include/linux/spinlock.h:351 [inline]
       folio_lruvec_lock+0x1ba/0x3b0 mm/memcontrol.c:1323
       __split_huge_page mm/huge_memory.c:2538 [inline]
       split_huge_page_to_list+0x103b/0x49e0 mm/huge_memory.c:2772
       split_folio_to_list include/linux/huge_mm.h:400 [inline]
       split_folio include/linux/huge_mm.h:405 [inline]
       truncate_inode_partial_folio+0x544/0x760 mm/truncate.c:242
       shmem_undo_range+0x723/0x1190 mm/shmem.c:1026
       shmem_truncate_range mm/shmem.c:1120 [inline]
       shmem_setattr+0xd43/0x1050 mm/shmem.c:1205
       notify_change+0x742/0x11c0 fs/attr.c:485
       do_truncate+0x15c/0x220 fs/open.c:66
       do_sys_ftruncate+0x6a2/0x790 fs/open.c:194
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #2 (&xa->xa_lock#7){..-.}-{2:2}:
       __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
       _raw_spin_lock_irq+0x36/0x50 kernel/locking/spinlock.c:170
       spin_lock_irq include/linux/spinlock.h:376 [inline]
       filemap_remove_folio+0xbf/0x250 mm/filemap.c:259
       truncate_inode_folio+0x49/0x70 mm/truncate.c:195
       shmem_undo_range+0x363/0x1190 mm/shmem.c:1004
       shmem_truncate_range mm/shmem.c:1120 [inline]
       shmem_evict_inode+0x334/0xb10 mm/shmem.c:1250
       evict+0x2ed/0x6b0 fs/inode.c:665
       iput_final fs/inode.c:1791 [inline]
       iput.part.0+0x55e/0x7a0 fs/inode.c:1817
       iput+0x5c/0x80 fs/inode.c:1807
       dentry_unlink_inode+0x292/0x430 fs/dcache.c:401
       __dentry_kill+0x3b8/0x640 fs/dcache.c:607
       dentry_kill fs/dcache.c:745 [inline]
       dput+0x703/0xfd0 fs/dcache.c:913
       do_renameat2+0xc4c/0xdc0 fs/namei.c:5011
       __do_sys_rename fs/namei.c:5055 [inline]
       __se_sys_rename fs/namei.c:5053 [inline]
       __x64_sys_rename+0x81/0xa0 fs/namei.c:5053
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (&sb->s_type->i_lock_key){+.+.}-{2:2}:
       __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
       _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
       spin_lock include/linux/spinlock.h:351 [inline]
       inode_sub_bytes+0x28/0x100 fs/stat.c:816
       __dquot_free_space+0x8f7/0xaf0 fs/quota/dquot.c:1881
       dquot_free_space_nodirty include/linux/quotaops.h:379 [inline]
       dquot_free_block_nodirty include/linux/quotaops.h:390 [inline]
       shmem_inode_unacct_blocks mm/shmem.c:243 [inline]
       shmem_recalc_inode+0x196/0x350 mm/shmem.c:420
       shmem_undo_range+0x558/0x1190 mm/shmem.c:1114
       shmem_truncate_range mm/shmem.c:1120 [inline]
       shmem_evict_inode+0x334/0xb10 mm/shmem.c:1250
       evict+0x2ed/0x6b0 fs/inode.c:665
       iput_final fs/inode.c:1791 [inline]
       iput.part.0+0x55e/0x7a0 fs/inode.c:1817
       iput+0x5c/0x80 fs/inode.c:1807
       dentry_unlink_inode+0x292/0x430 fs/dcache.c:401
       __dentry_kill+0x3b8/0x640 fs/dcache.c:607
       dentry_kill fs/dcache.c:745 [inline]
       dput+0x703/0xfd0 fs/dcache.c:913
       do_renameat2+0xc4c/0xdc0 fs/namei.c:5011
       __do_sys_rename fs/namei.c:5055 [inline]
       __se_sys_rename fs/namei.c:5053 [inline]
       __x64_sys_rename+0x81/0xa0 fs/namei.c:5053
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&info->lock){....}-{2:2}:
       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+0x2e3d/0x5de0 kernel/locking/lockdep.c:5144
       lock_acquire kernel/locking/lockdep.c:5761 [inline]
       lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5726
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162
       shmem_uncharge+0x28/0x2b0 mm/shmem.c:450
       __split_huge_page mm/huge_memory.c:2549 [inline]
       split_huge_page_to_list+0x3832/0x49e0 mm/huge_memory.c:2772
       split_folio_to_list include/linux/huge_mm.h:400 [inline]
       split_folio include/linux/huge_mm.h:405 [inline]
       truncate_inode_partial_folio+0x544/0x760 mm/truncate.c:242
       shmem_undo_range+0x723/0x1190 mm/shmem.c:1026
       shmem_truncate_range mm/shmem.c:1120 [inline]
       shmem_setattr+0xd43/0x1050 mm/shmem.c:1205
       notify_change+0x742/0x11c0 fs/attr.c:485
       do_truncate+0x15c/0x220 fs/open.c:66
       do_sys_ftruncate+0x6a2/0x790 fs/open.c:194
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Chain exists of:
  &info->lock --> &xa->xa_lock#7 --> &lruvec->lru_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&lruvec->lru_lock);
                               lock(&xa->xa_lock#7);
                               lock(&lruvec->lru_lock);
  lock(&info->lock);

 *** DEADLOCK ***

5 locks held by /5027:
 #0: ffff8880762b4410 (sb_writers#5){.+.+}-{0:0}, at: do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 #0: ffff8880762b4410 (sb_writers#5){.+.+}-{0:0}, at: do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 #1: ffff88807dbd8a50 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:771 [inline]
 #1: ffff88807dbd8a50 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: do_truncate+0x14b/0x220 fs/open.c:64
 #2: ffff88807dbd8cf0 (&mapping->i_mmap_rwsem){++++}-{3:3}, at: i_mmap_lock_read include/linux/fs.h:501 [inline]
 #2: ffff88807dbd8cf0 (&mapping->i_mmap_rwsem){++++}-{3:3}, at: split_huge_page_to_list+0x7d5/0x49e0 mm/huge_memory.c:2712
 #3: ffff88807dbd8b60 (&xa->xa_lock#7){..-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
 #3: ffff88807dbd8b60 (&xa->xa_lock#7){..-.}-{2:2}, at: split_huge_page_to_list+0x980/0x49e0 mm/huge_memory.c:2744
 #4: ffff88801526c068 (&lruvec->lru_lock){....}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
 #4: ffff88801526c068 (&lruvec->lru_lock){....}-{2:2}, at: folio_lruvec_lock+0x1ba/0x3b0 mm/memcontrol.c:1323

stack backtrace:
CPU: 0 PID: 5027 Comm:  Not tainted 6.5.0-rc1-next-20230714-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/03/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 check_noncircular+0x311/0x3f0 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+0x2e3d/0x5de0 kernel/locking/lockdep.c:5144
 lock_acquire kernel/locking/lockdep.c:5761 [inline]
 lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5726
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162
 shmem_uncharge+0x28/0x2b0 mm/shmem.c:450
 __split_huge_page mm/huge_memory.c:2549 [inline]
 split_huge_page_to_list+0x3832/0x49e0 mm/huge_memory.c:2772
 split_folio_to_list include/linux/huge_mm.h:400 [inline]
 split_folio include/linux/huge_mm.h:405 [inline]
 truncate_inode_partial_folio+0x544/0x760 mm/truncate.c:242
 shmem_undo_range+0x723/0x1190 mm/shmem.c:1026
 shmem_truncate_range mm/shmem.c:1120 [inline]
 shmem_setattr+0xd43/0x1050 mm/shmem.c:1205
 notify_change+0x742/0x11c0 fs/attr.c:485
 do_truncate+0x15c/0x220 fs/open.c:66
 do_sys_ftruncate+0x6a2/0x790 fs/open.c:194
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fcc0ae38b99
Code: 48 83 c4 28 c3 e8 67 17 00 00 0f 1f 80 00 00 00 00 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:00007ffcd4272e58 EFLAGS: 00000246 ORIG_RAX: 000000000000004d
RAX: ffffffffffffffda RBX: 00007ffcd4272e60 RCX: 00007fcc0ae38b99
RDX: 00007fcc0ae38b99 RSI: 0000000000008979 RDI: 0000000000000003
RBP: 00007ffcd4272e68 R08: 00007fcc0ae05c10 R09: 00007fcc0ae05c10
R10: 0000000000000000 R11: 000000


---
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If the bug is already fixed, let syzbot know by replying with:
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