linux-kernel - Re: [syzbot] [xfs?] [mm?] WARNING: bad unlock balance in __mm

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Message-ID: <67c6fdc6.050a0220.38b91b.0180.GAE@google.com>
Date: Tue, 04 Mar 2025 05:19:02 -0800
From: syzbot <syzbot+8f9f411152c9539f4e59@...kaller.appspotmail.com>
To: eadavis@...com, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [xfs?] [mm?] WARNING: bad unlock balance in __mm_populate

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING: bad unlock balance in __mm_populate

XFS (loop0): Mounting V5 Filesystem bfdc47fc-10d8-4eed-a562-11a831b3f791
XFS (loop0): Ending clean mount
XFS (loop0): Quotacheck needed: Please wait.
XFS (loop0): Quotacheck: Done.
mm: 000000001ba89fe1, mmap lock held: 0, locked: 1, __mm_populate
=====================================
WARNING: bad unlock balance detected!
6.14.0-rc4-syzkaller-00034-ge056da87c780-dirty #0 Not tainted
-------------------------------------
syz.0.16/7463 is trying to release lock (&mm->mmap_lock) at:
[<ffff800080a63ca4>] mmap_read_unlock include/linux/mmap_lock.h:217 [inline]
[<ffff800080a63ca4>] __mm_populate+0x378/0x42c mm/gup.c:2045
but there are no more locks to release!

other info that might help us debug this:
no locks held by syz.0.16/7463.

stack backtrace:
CPU: 1 UID: 0 PID: 7463 Comm: syz.0.16 Not tainted 6.14.0-rc4-syzkaller-00034-ge056da87c780-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:466 (C)
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0xe4/0x150 lib/dump_stack.c:120
 dump_stack+0x1c/0x28 lib/dump_stack.c:129
 print_unlock_imbalance_bug+0x254/0x2ac kernel/locking/lockdep.c:5289
 __lock_release kernel/locking/lockdep.c:5518 [inline]
 lock_release+0x410/0x9e4 kernel/locking/lockdep.c:5872
 up_read+0x24/0x3c kernel/locking/rwsem.c:1619
 mmap_read_unlock include/linux/mmap_lock.h:217 [inline]
 __mm_populate+0x378/0x42c mm/gup.c:2045
 mm_populate include/linux/mm.h:3386 [inline]
 vm_mmap_pgoff+0x304/0x3c4 mm/util.c:580
 ksys_mmap_pgoff+0x3a4/0x5c8 mm/mmap.c:607
 __do_sys_mmap arch/arm64/kernel/sys.c:28 [inline]
 __se_sys_mmap arch/arm64/kernel/sys.c:21 [inline]
 __arm64_sys_mmap+0xf8/0x110 arch/arm64/kernel/sys.c:21
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
------------[ cut here ]------------
DEBUG_RWSEMS_WARN_ON(tmp < 0): count = 0xffffffffffffff00, magic = 0xffff0000d584dee0, owner = 0x1, curr 0xffff0000c4da5b80, list empty
WARNING: CPU: 1 PID: 7463 at kernel/locking/rwsem.c:1346 __up_read+0x3bc/0x5f8 kernel/locking/rwsem.c:1346
Modules linked in:
CPU: 1 UID: 0 PID: 7463 Comm: syz.0.16 Not tainted 6.14.0-rc4-syzkaller-00034-ge056da87c780-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __up_read+0x3bc/0x5f8 kernel/locking/rwsem.c:1346
lr : __up_read+0x3bc/0x5f8 kernel/locking/rwsem.c:1346
sp : ffff80009e0979e0
x29: ffff80009e097a60 x28: 1ffff00011f760cb x27: ffff80008fbb0000
x26: dfff800000000000 x25: ffffffffffffff00 x24: ffff0000d584df38
x23: ffff0000d584dee0 x22: ffffffffffffff00 x21: 0000000000000001
x20: ffff0000c4da5b80 x19: ffff0000d584dee0 x18: 0000000000000008
x17: 0000000000000000 x16: ffff8000832b41c0 x15: 0000000000000001
x14: 1ffff00013c12e94 x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000000003 x10: 0000000000ff0100 x9 : 3ef51d0da1723500
x8 : 3ef51d0da1723500 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff80009e097198 x4 : ffff80008fc9f780 x3 : ffff8000832461d4
x2 : 0000000000000001 x1 : 0000000100000001 x0 : 0000000000000000
Call trace:
 __up_read+0x3bc/0x5f8 kernel/locking/rwsem.c:1346 (P)
 up_read+0x2c/0x3c kernel/locking/rwsem.c:1620
 mmap_read_unlock include/linux/mmap_lock.h:217 [inline]
 __mm_populate+0x378/0x42c mm/gup.c:2045
 mm_populate include/linux/mm.h:3386 [inline]
 vm_mmap_pgoff+0x304/0x3c4 mm/util.c:580
 ksys_mmap_pgoff+0x3a4/0x5c8 mm/mmap.c:607
 __do_sys_mmap arch/arm64/kernel/sys.c:28 [inline]
 __se_sys_mmap arch/arm64/kernel/sys.c:21 [inline]
 __arm64_sys_mmap+0xf8/0x110 arch/arm64/kernel/sys.c:21
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
irq event stamp: 75153
hardirqs last  enabled at (75153): [<ffff8000804aebf4>] __up_console_sem kernel/printk/printk.c:344 [inline]
hardirqs last  enabled at (75153): [<ffff8000804aebf4>] __console_unlock+0x70/0xc4 kernel/printk/printk.c:2869
hardirqs last disabled at (75152): [<ffff8000804aebdc>] __up_console_sem kernel/printk/printk.c:342 [inline]
hardirqs last disabled at (75152): [<ffff8000804aebdc>] __console_unlock+0x58/0xc4 kernel/printk/printk.c:2869
softirqs last  enabled at (74970): [<ffff8000801283e0>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (74968): [<ffff8000801283ac>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
---[ end trace 0000000000000000 ]---


Tested on:

commit:         e056da87 Merge remote-tracking branch 'will/for-next/p..
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=11f31464580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d6b7e15dc5b5e776
dashboard link: https://syzkaller.appspot.com/bug?extid=8f9f411152c9539f4e59
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64
patch:          https://syzkaller.appspot.com/x/patch.diff?x=13f51464580000