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Date:   Wed, 05 Jul 2023 20:12:53 -0700
Message-ID: <000000000000607ff905ffc8e477@google.com>
Subject: [syzbot] [mm?] WARNING: suspicious RCU usage in mas_walk (2)
From:   syzbot <syzbot+8645fe63c4d22c8d27b8@syzkaller.appspotmail.com>
To:     akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, syzkaller-bugs@googlegroups.com
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Precedence: bulk

Hello,

syzbot found the following issue on:

HEAD commit:    a901a3568fd2 Merge tag 'iomap-6.5-merge-1' of git://git.ke..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=105632c8a80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=db74cd5aa6878807
dashboard link: https://syzkaller.appspot.com/bug?extid=8645fe63c4d22c8d27b8
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3e7b15164da6/disk-a901a356.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9880c1d81d68/vmlinux-a901a356.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6d5b0c0d9670/bzImage-a901a356.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8645fe63c4d22c8d27b8@syzkaller.appspotmail.com

SELinux:  policy capability cgroup_seclabel=1
SELinux:  policy capability nnp_nosuid_transition=1
SELinux:  policy capability genfs_seclabel_symlinks=0
SELinux:  policy capability ioctl_skip_cloexec=0
=============================
WARNING: suspicious RCU usage
6.4.0-syzkaller-10173-ga901a3568fd2 #0 Not tainted
-----------------------------
lib/maple_tree.c:860 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
no locks held by init/1.

stack backtrace:
CPU: 1 PID: 1 Comm: init Not tainted 6.4.0-syzkaller-10173-ga901a3568fd2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x136/0x150 lib/dump_stack.c:106
 lockdep_rcu_suspicious+0x208/0x3a0 kernel/locking/lockdep.c:6719
 mas_root lib/maple_tree.c:860 [inline]
 mas_root lib/maple_tree.c:858 [inline]
 mas_start lib/maple_tree.c:1402 [inline]
 mas_start lib/maple_tree.c:1392 [inline]
 mas_state_walk lib/maple_tree.c:3861 [inline]
 mas_walk+0x4e8/0x7c0 lib/maple_tree.c:4980
 mas_find_setup lib/maple_tree.c:5924 [inline]
 mas_find+0x1cb/0x340 lib/maple_tree.c:5965
 vma_next include/linux/mm.h:865 [inline]
 validate_mm+0xd2/0x470 mm/mmap.c:301
 do_vmi_align_munmap+0x1199/0x1680 mm/mmap.c:2561
 do_vmi_munmap+0x266/0x430 mm/mmap.c:2619
 __vm_munmap+0x137/0x380 mm/mmap.c:2899
 __do_sys_munmap mm/mmap.c:2916 [inline]
 __se_sys_munmap mm/mmap.c:2913 [inline]
 __x64_sys_munmap+0x62/0x80 mm/mmap.c:2913
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f36cc8e9817
Code: ff ff 76 10 48 8b 15 10 36 0d 00 f7 d8 64 89 02 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e1 35 0d 00 f7 d8 64 89 01 48
RSP: 002b:00007fff12a54cf8 EFLAGS: 00000246 ORIG_RAX: 000000000000000b
RAX: ffffffffffffffda RBX: 000000000000001f RCX: 00007f36cc8e9817
RDX: 0000000000000000 RSI: 00000000000415ce RDI: 00007f36cc6b1000
RBP: 00005613cf216bf0 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f36cc6b1000 R15: 00007f36cc72a16d
 </TASK>

=============================
WARNING: suspicious RCU usage
6.4.0-syzkaller-10173-ga901a3568fd2 #0 Not tainted
-----------------------------
lib/maple_tree.c:816 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
no locks held by init/1.

stack backtrace:
CPU: 0 PID: 1 Comm: init Not tainted 6.4.0-syzkaller-10173-ga901a3568fd2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x136/0x150 lib/dump_stack.c:106
 lockdep_rcu_suspicious+0x208/0x3a0 kernel/locking/lockdep.c:6719
 mt_slot lib/maple_tree.c:816 [inline]
 mt_slot lib/maple_tree.c:813 [inline]
 mtree_range_walk+0x602/0x940 lib/maple_tree.c:2976
 mas_state_walk lib/maple_tree.c:3868 [inline]
 mas_walk+0x393/0x7c0 lib/maple_tree.c:4980
 mas_find_setup lib/maple_tree.c:5924 [inline]
 mas_find+0x1cb/0x340 lib/maple_tree.c:5965
 vma_next include/linux/mm.h:865 [inline]
 validate_mm+0xd2/0x470 mm/mmap.c:301
 do_vmi_align_munmap+0x1199/0x1680 mm/mmap.c:2561
 do_vmi_munmap+0x266/0x430 mm/mmap.c:2619
 __vm_munmap+0x137/0x380 mm/mmap.c:2899
 __do_sys_munmap mm/mmap.c:2916 [inline]
 __se_sys_munmap mm/mmap.c:2913 [inline]
 __x64_sys_munmap+0x62/0x80 mm/mmap.c:2913
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f36cc8e9817
Code: ff ff 76 10 48 8b 15 10 36 0d 00 f7 d8 64 89 02 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e1 35 0d 00 f7 d8 64 89 01 48
RSP: 002b:00007fff12a54cf8 EFLAGS: 00000246 ORIG_RAX: 000000000000000b
RAX: ffffffffffffffda RBX: 000000000000001f RCX: 00007f36cc8e9817
RDX: 0000000000000000 RSI: 00000000000415ce RDI: 00007f36cc6b1000
RBP: 00005613cf216bf0 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f36cc6b1000 R15: 00007f36cc72a16d
 </TASK>


---
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