Subject: [syzbot] [mm?] possible deadlock in __mmap_lock_do_trace_released

From: syzbot <[email-masked]>
Date: Tue, 02 Jul 2024 11:54:26 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    a12978712d90 selftests/bpf: Move ARRAY_SIZE to bpf_misc.h
git tree:       bpf-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=130457fa980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=736daf12bd72e034
dashboard link: https://syzkaller.appspot.com/bug?extid=16b6ab88e66b34d09014
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=125718be980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14528876980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9d845a55bf58/disk-a1297871.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/12cb27bdb2de/vmlinux-a1297871.xz
kernel image: https://storage.googleapis.com/syzbot-assets/db09a1fa448c/bzImage-a1297871.xz

The issue was bisected to:

commit 21c38a3bd4ee3fb7337d013a638302fb5e5f9dc2
Author: Jesper Dangaard Brouer <[email-masked]>
Date:   Wed May 1 14:04:11 2024 +0000

    cgroup/rstat: add cgroup_rstat_cpu_lock helpers and tracepoints

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=14ecc085980000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=16ecc085980000
console output: https://syzkaller.appspot.com/x/log.txt?x=12ecc085980000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]
Fixes: 21c38a3bd4ee ("cgroup/rstat: add cgroup_rstat_cpu_lock helpers and tracepoints")

============================================
WARNING: possible recursive locking detected
6.10.0-rc2-syzkaller-00797-ga12978712d90 #0 Not tainted
--------------------------------------------
syz-executor646/5097 is trying to acquire lock:
ffff8880b94387e8 (lock#9){+.+.}-{2:2}, at: local_lock_acquire include/linux/local_lock_internal.h:29 [inline]
ffff8880b94387e8 (lock#9){+.+.}-{2:2}, at: __mmap_lock_do_trace_released+0x83/0x620 mm/mmap_lock.c:243

but task is already holding lock:
ffff8880b94387e8 (lock#9){+.+.}-{2:2}, at: local_lock_acquire include/linux/local_lock_internal.h:29 [inline]
ffff8880b94387e8 (lock#9){+.+.}-{2:2}, at: __mmap_lock_do_trace_released+0x83/0x620 mm/mmap_lock.c:243

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(lock#9);
  lock(lock#9);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

5 locks held by syz-executor646/5097:
 #0: ffff8880182eb118 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock include/linux/mmap_lock.h:144 [inline]
 #0: ffff8880182eb118 (&mm->mmap_lock){++++}-{3:3}, at: acct_collect+0x1cf/0x830 kernel/acct.c:563
 #1: ffff8880b94387e8 (lock#9){+.+.}-{2:2}, at: local_lock_acquire include/linux/local_lock_internal.h:29 [inline]
 #1: ffff8880b94387e8 (lock#9){+.+.}-{2:2}, at: __mmap_lock_do_trace_released+0x83/0x620 mm/mmap_lock.c:243
 #2: ffffffff8e333fa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #2: ffffffff8e333fa0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #2: ffffffff8e333fa0 (rcu_read_lock){....}-{1:2}, at: get_memcg_path_buf mm/mmap_lock.c:139 [inline]
 #2: ffffffff8e333fa0 (rcu_read_lock){....}-{1:2}, at: get_mm_memcg_path+0xb1/0x600 mm/mmap_lock.c:209
 #3: ffffffff8e333fa0 (rcu_read_lock){....}-{1:2}, at: trace_call_bpf+0xbc/0x8a0
 #4: ffff8880182eb118 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:163 [inline]
 #4: ffff8880182eb118 (&mm->mmap_lock){++++}-{3:3}, at: stack_map_get_build_id_offset+0x237/0x9d0 kernel/bpf/stackmap.c:141

stack backtrace:
CPU: 0 PID: 5097 Comm: syz-executor646 Not tainted 6.10.0-rc2-syzkaller-00797-ga12978712d90 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 check_deadlock kernel/locking/lockdep.c:3062 [inline]
 validate_chain+0x15d3/0x5900 kernel/locking/lockdep.c:3856
 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
 local_lock_acquire include/linux/local_lock_internal.h:29 [inline]
 __mmap_lock_do_trace_released+0x9c/0x620 mm/mmap_lock.c:243
 __mmap_lock_trace_released include/linux/mmap_lock.h:42 [inline]
 mmap_read_unlock include/linux/mmap_lock.h:170 [inline]
 bpf_mmap_unlock_mm kernel/bpf/mmap_unlock_work.h:52 [inline]
 stack_map_get_build_id_offset+0x9c7/0x9d0 kernel/bpf/stackmap.c:173
 __bpf_get_stack+0x4ad/0x5a0 kernel/bpf/stackmap.c:449
 bpf_prog_e6cf5f9c69743609+0x42/0x46
 bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline]
 __bpf_prog_run include/linux/filter.h:691 [inline]
 bpf_prog_run include/linux/filter.h:698 [inline]
 bpf_prog_run_array include/linux/bpf.h:2104 [inline]
 trace_call_bpf+0x369/0x8a0 kernel/trace/bpf_trace.c:147
 perf_trace_run_bpf_submit+0x7c/0x1d0 kernel/events/core.c:10269
 perf_trace_mmap_lock+0x3d7/0x510 include/trace/events/mmap_lock.h:16
 trace_mmap_lock_released include/trace/events/mmap_lock.h:50 [inline]
 __mmap_lock_do_trace_released+0x5bb/0x620 mm/mmap_lock.c:243
 __mmap_lock_trace_released include/linux/mmap_lock.h:42 [inline]
 mmap_read_unlock include/linux/mmap_lock.h:170 [inline]
 acct_collect+0x81d/0x830 kernel/acct.c:566
 do_exit+0x936/0x27e0 kernel/exit.c:853
 do_group_exit+0x207/0x2c0 kernel/exit.c:1023
 __do_sys_exit_group kernel/exit.c:1034 [inline]
 __se_sys_exit_group kernel/exit.c:1032 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1032
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8fac26d039
Code: 90 49 c7 c0 b8 ff ff ff be e7 00 00 00 ba 3c 00 00 00 eb 12 0f 1f 44 00 00 89 d0 0f 05 48 3d 00 f0 ff ff 77 1c f4 89 f0 0f 05 <48> 3d 00 f0 ff ff 76 e7 f7 d8 64 41 89 00 eb df 0f 1f 80 00 00 00
RSP: 002b:00007ffd95d56e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f8fac26d039
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
RBP: 00007f8fac2e82b0 R08: ffffffffffffffb8 R09: 00000000000000a0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f8fac2e82b0
R13: 0000000000000000 R14: 00007f8fac2e8d20 R15: 00007f8fac23e1e0
 </TASK>

---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at [email-masked].

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup