[syzbot] [mm?] possible deadlock in __unmap_hugepage_range

[syzbot <syzbot+a1deb5533794ff31868e@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    8bf1262c53f5 Add linux-next specific files for 20240124
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1218a7abe80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ff4b59a824278780
dashboard link: https://syzkaller.appspot.com/bug?extid=a1deb5533794ff31868e
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=151a9cf7e80000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=164b70cfe80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7696d711072d/disk-8bf1262c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/92cd47c28072/vmlinux-8bf1262c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/add5c7493418/bzImage-8bf1262c.xz

The issue was bisected to:

commit 947b031634e7af3d265275c26ec17e2f96fdb5a1
Author: Breno Leitao <leitao@debian.org>
Date:   Wed Jan 17 17:10:57 2024 +0000

    mm/hugetlb: restore the reservation if needed

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=139660a0180000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=105660a0180000
console output: https://syzkaller.appspot.com/x/log.txt?x=179660a0180000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a1deb5533794ff31868e@syzkaller.appspotmail.com
Fixes: 947b031634e7 ("mm/hugetlb: restore the reservation if needed")

======================================================
WARNING: possible circular locking dependency detected
6.8.0-rc1-next-20240124-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor338/5065 is trying to acquire lock:
ffffffff8d925b00 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:303 [inline]
ffffffff8d925b00 (fs_reclaim){+.+.}-{0:0}, at: slab_pre_alloc_hook mm/slub.c:3762 [inline]
ffffffff8d925b00 (fs_reclaim){+.+.}-{0:0}, at: slab_alloc_node mm/slub.c:3843 [inline]
ffffffff8d925b00 (fs_reclaim){+.+.}-{0:0}, at: kmalloc_trace+0x51/0x330 mm/slub.c:4008

but task is already holding lock:
ffff888024054e28 (ptlock_ptr(ptdesc)){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
ffff888024054e28 (ptlock_ptr(ptdesc)){+.+.}-{2:2}, at: huge_pte_lock include/linux/hugetlb.h:1232 [inline]
ffff888024054e28 (ptlock_ptr(ptdesc)){+.+.}-{2:2}, at: __unmap_hugepage_range+0x4e5/0x1bf0 mm/hugetlb.c:5611

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (ptlock_ptr(ptdesc)){+.+.}-{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]
       pmd_lock include/linux/mm.h:3036 [inline]
       __split_huge_pmd+0x21f/0x3090 mm/huge_memory.c:2625
       split_huge_pmd_address mm/huge_memory.c:2658 [inline]
       split_huge_pmd_if_needed mm/huge_memory.c:2670 [inline]
       split_huge_pmd_if_needed mm/huge_memory.c:2661 [inline]
       vma_adjust_trans_huge+0x2da/0x560 mm/huge_memory.c:2682
       __split_vma+0xcb9/0x1190 mm/mmap.c:2363
       split_vma mm/mmap.c:2399 [inline]
       vma_modify+0x261/0x460 mm/mmap.c:2434
       vma_modify_flags include/linux/mm.h:3283 [inline]
       mprotect_fixup+0x228/0xc90 mm/mprotect.c:635
       do_mprotect_pkey+0x8a4/0xdc0 mm/mprotect.c:809
       __do_sys_mprotect mm/mprotect.c:830 [inline]
       __se_sys_mprotect mm/mprotect.c:827 [inline]
       __x64_sys_mprotect+0x78/0xc0 mm/mprotect.c:827
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x6d/0x75

-> #1 (&mapping->i_mmap_rwsem){++++}-{3:3}:
       down_write+0x3a/0x50 kernel/locking/rwsem.c:1579
       i_mmap_lock_write include/linux/fs.h:512 [inline]
       dma_resv_lockdep+0x292/0x620 drivers/dma-buf/dma-resv.c:787
       do_one_initcall+0x128/0x690 init/main.c:1236
       do_initcall_level init/main.c:1298 [inline]
       do_initcalls init/main.c:1314 [inline]
       do_basic_setup init/main.c:1333 [inline]
       kernel_init_freeable+0x698/0xc30 init/main.c:1551
       kernel_init+0x1c/0x2a0 init/main.c:1441
       ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:242

-> #0 (fs_reclaim){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain kernel/locking/lockdep.c:3869 [inline]
       __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
       lock_acquire kernel/locking/lockdep.c:5754 [inline]
       lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719
       __fs_reclaim_acquire mm/page_alloc.c:3728 [inline]
       fs_reclaim_acquire+0x102/0x150 mm/page_alloc.c:3742
       might_alloc include/linux/sched/mm.h:303 [inline]
       slab_pre_alloc_hook mm/slub.c:3762 [inline]
       slab_alloc_node mm/slub.c:3843 [inline]
       kmalloc_trace+0x51/0x330 mm/slub.c:4008
       kmalloc include/linux/slab.h:590 [inline]
       allocate_file_region_entries+0x1a3/0x620 mm/hugetlb.c:666
       region_chg+0x85/0x140 mm/hugetlb.c:786
       __vma_reservation_common+0x443/0x740 mm/hugetlb.c:2832
       vma_needs_reservation mm/hugetlb.c:2899 [inline]
       __unmap_hugepage_range+0xfdb/0x1bf0 mm/hugetlb.c:5681
       unmap_single_vma+0x24b/0x2b0 mm/memory.c:1813
       unmap_vmas+0x22f/0x490 mm/memory.c:1861
       exit_mmap+0x1c1/0xbe0 mm/mmap.c:3258
       __mmput+0x12a/0x4d0 kernel/fork.c:1343
       mmput+0x62/0x70 kernel/fork.c:1365
       exit_mm kernel/exit.c:569 [inline]
       do_exit+0x999/0x2ac0 kernel/exit.c:858
       do_group_exit+0xd3/0x2a0 kernel/exit.c:1020
       __do_sys_exit_group kernel/exit.c:1031 [inline]
       __se_sys_exit_group kernel/exit.c:1029 [inline]
       __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1029
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x6d/0x75

other info that might help us debug this:

Chain exists of:
  fs_reclaim --> &mapping->i_mmap_rwsem --> ptlock_ptr(ptdesc)

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(ptlock_ptr(ptdesc));
                               lock(&mapping->i_mmap_rwsem);
                               lock(ptlock_ptr(ptdesc));
  lock(fs_reclaim);

 *** DEADLOCK ***

4 locks held by syz-executor338/5065:
 #0: ffff88806c3b27a0 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock include/linux/mmap_lock.h:168 [inline]
 #0: ffff88806c3b27a0 (&mm->mmap_lock){++++}-{3:3}, at: exit_mmap+0x107/0xbe0 mm/mmap.c:3242
 #1: ffff88806c0e20e8 (&resv_map->rw_sema){++++}-{3:3}, at: hugetlb_vma_lock_write mm/hugetlb.c:300 [inline]
 #1: ffff88806c0e20e8 (&resv_map->rw_sema){++++}-{3:3}, at: hugetlb_vma_lock_write+0x105/0x140 mm/hugetlb.c:291
 #2: ffff88802507c3c8 (&hugetlbfs_i_mmap_rwsem_key){+.+.}-{3:3}, at: i_mmap_lock_write include/linux/fs.h:512 [inline]
 #2: ffff88802507c3c8 (&hugetlbfs_i_mmap_rwsem_key){+.+.}-{3:3}, at: __hugetlb_zap_begin+0x242/0x2b0 mm/hugetlb.c:5726
 #3: ffff888024054e28 (ptlock_ptr(ptdesc)){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
 #3: ffff888024054e28 (ptlock_ptr(ptdesc)){+.+.}-{2:2}, at: huge_pte_lock include/linux/hugetlb.h:1232 [inline]
 #3: ffff888024054e28 (ptlock_ptr(ptdesc)){+.+.}-{2:2}, at: __unmap_hugepage_range+0x4e5/0x1bf0 mm/hugetlb.c:5611

stack backtrace:
CPU: 0 PID: 5065 Comm: syz-executor338 Not tainted 6.8.0-rc1-next-20240124-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain kernel/locking/lockdep.c:3869 [inline]
 __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
 lock_acquire kernel/locking/lockdep.c:5754 [inline]
 lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719
 __fs_reclaim_acquire mm/page_alloc.c:3728 [inline]
 fs_reclaim_acquire+0x102/0x150 mm/page_alloc.c:3742
 might_alloc include/linux/sched/mm.h:303 [inline]
 slab_pre_alloc_hook mm/slub.c:3762 [inline]
 slab_alloc_node mm/slub.c:3843 [inline]
 kmalloc_trace+0x51/0x330 mm/slub.c:4008
 kmalloc include/linux/slab.h:590 [inline]
 allocate_file_region_entries+0x1a3/0x620 mm/hugetlb.c:666
 region_chg+0x85/0x140 mm/hugetlb.c:786
 __vma_reservation_common+0x443/0x740 mm/hugetlb.c:2832
 vma_needs_reservation mm/hugetlb.c:2899 [inline]
 __unmap_hugepage_range+0xfdb/0x1bf0 mm/hugetlb.c:5681
 unmap_single_vma+0x24b/0x2b0 mm/memory.c:1813
 unmap_vmas+0x22f/0x490 mm/memory.c:1861
 exit_mmap+0x1c1/0xbe0 mm/mmap.c:3258
 __mmput+0x12a/0x4d0 kernel/fork.c:1343
 mmput+0x62/0x70 kernel/fork.c:1365
 exit_mm kernel/exit.c:569 [inline]
 do_exit+0x999/0x2ac0 kernel/exit.c:858
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1020
 __do_sys_exit_group kernel/exit.c:1031 [inline]
 __se_sys_exit_group kernel/exit.c:1029 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1029
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f39d1ba2c79
Code: Unable to access opcode bytes at 0x7f39d1ba2c4f.
RSP: 002b:00007ffcc6ad06f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f39d1ba2c79
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
RBP: 00007f39d1c1d270 R08: ffffffffffffffb8 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000246 R12: 00007f39d1c1d270
R13: 0000000000000000 R14: 00007f39d1c1dcc0 R15: 00007f39d1b74a60
 </TASK>
BUG: sleeping function called from invalid context at include/linux/sched/mm.h:306
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 5065, name: syz-executor338
preempt_count: 1, expected: 0
RCU nest depth: 0, expected: 0
INFO: lockdep is turned off.
Preemption disabled at:
[<0000000000000000>] 0x0
CPU: 0 PID: 5065 Comm: syz-executor338 Not tainted 6.8.0-rc1-next-20240124-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x125/0x1b0 lib/dump_stack.c:106
 __might_resched+0x3c0/0x5e0 kernel/sched/core.c:10178
 might_alloc include/linux/sched/mm.h:306 [inline]
 might_alloc include/linux/sched/mm.h:301 [inline]
 slab_pre_alloc_hook mm/slub.c:3762 [inline]
 slab_alloc_node mm/slub.c:3843 [inline]
 kmalloc_trace+0x2a3/0x330 mm/slub.c:4008
 kmalloc include/linux/slab.h:590 [inline]
 allocate_file_region_entries+0x1a3/0x620 mm/hugetlb.c:666
 region_chg+0x85/0x140 mm/hugetlb.c:786
 __vma_reservation_common+0x443/0x740 mm/hugetlb.c:2832
 vma_needs_reservation mm/hugetlb.c:2899 [inline]
 __unmap_hugepage_range+0xfdb/0x1bf0 mm/hugetlb.c:5681
 unmap_single_vma+0x24b/0x2b0 mm/memory.c:1813
 unmap_vmas+0x22f/0x490 mm/memory.c:1861
 exit_mmap+0x1c1/0xbe0 mm/mmap.c:3258
 __mmput+0x12a/0x4d0 kernel/fork.c:1343
 mmput+0x62/0x70 kernel/fork.c:1365
 exit_mm kernel/exit.c:569 [inline]
 do_exit+0x999/0x2ac0 kernel/exit.c:858
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1020
 __do_sys_exit_group kernel/exit.c:1031 [inline]
 __se_sys_exit_group kernel/exit.c:1029 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1029
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f39d1ba2c79
Code: Unable to access opcode bytes at 0x7f39d1ba2c4f.
RSP: 002b:00007ffcc6ad06f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f39d1ba2c79
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
RBP: 00007f39d1c1d270 R08: ffffffffffffffb8 R09: 0000000000000000
R10: 0000000000000003 R11: 0


---
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