[v6.1] INFO: rcu detected stall in do_mas_munmap (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 344a09659766 Linux 6.1.131
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=169d0a4c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=1eebf09bc04ebd78
dashboard link: https://syzkaller.appspot.com/bug?extid=009b2a7f9d8a0615cf9b
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bccba205a29a/disk-344a0965.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bdca79b3b5db/vmlinux-344a0965.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6c2271a91ef3/bzImage-344a0965.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+009b2a...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7216/1:b..l
(detected by 1, t=10502 jiffies, g=39629, q=437 ncpus=2)
task:rm state:R running task stack:22968 pid:7216 ppid:7160 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5243 [inline]
__schedule+0x143f/0x4570 kernel/sched/core.c:6560
preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6872
irqentry_exit+0x53/0x80 kernel/entry/common.c:439
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5666
Code: 2b 00 74 08 4c 89 f7 e8 4f 55 77 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc90004bde3c0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff9200097bc84 RCX: 1ffff9200097bc24
RDX: dffffc0000000000 RSI: ffffffff8b0c2ec0 RDI: ffffffff8b5f6f80
RBP: ffffc90004bde510 R08: dffffc0000000000 R09: fffffbfff225724d
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff9200097bc80
R13: dffffc0000000000 R14: ffffc90004bde420 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
rcu_read_lock include/linux/rcupdate.h:791 [inline]
is_bpf_text_address+0x3e/0x2a0 kernel/bpf/core.c:735
kernel_text_address+0x9f/0xd0 kernel/extable.c:125
__kernel_text_address+0x9/0x40 kernel/extable.c:79
unwind_get_return_address+0x49/0x80 arch/x86/kernel/unwind_orc.c:323
arch_stack_walk+0xf3/0x140 arch/x86/kernel/stacktrace.c:26
stack_trace_save+0x113/0x1c0 kernel/stacktrace.c:122
kasan_save_stack+0x3b/0x60 mm/kasan/common.c:45
__kasan_record_aux_stack+0xb0/0xc0 mm/kasan/generic.c:486
call_rcu+0x163/0xa10 kernel/rcu/tree.c:2845
mas_wr_node_store lib/maple_tree.c:4220 [inline]
mas_wr_modify+0x2a4d/0x4b90 lib/maple_tree.c:4419
mas_store_prealloc+0x304/0x460 lib/maple_tree.c:5787
__vma_adjust+0x183f/0x1f40 mm/mmap.c:823
__split_vma+0x36c/0x4c0
do_mas_align_munmap+0x42f/0x15a0 mm/mmap.c:2468
do_mas_munmap+0x246/0x2b0 mm/mmap.c:2638
__mmap_region mm/mmap.c:2686 [inline]
mmap_region+0x8d4/0x2660 mm/mmap.c:2904
do_mmap+0x8c5/0xf60 mm/mmap.c:1424
vm_mmap_pgoff+0x1ca/0x2d0 mm/util.c:520
ksys_mmap_pgoff+0x4f5/0x6d0 mm/mmap.c:1470
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f04354a0b74
RSP: 002b:00007ffeade8ba38 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007ffeade8bae8 RCX: 00007f04354a0b74
RDX: 0000000000000003 RSI: 0000000000006000 RDI: 00007f04353ad000
RBP: 00007ffeade8c1d0 R08: 0000000000000003 R09: 000000000019d000
R10: 0000000000000812 R11: 0000000000000246 R12: 00007f04354835c0
R13: 00007ffeade8c258 R14: 000000000019d264 R15: 0000000000000000
</TASK>
rcu: rcu_preempt kthread starved for 9940 jiffies! g39629 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack:26712 pid:16 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5243 [inline]
__schedule+0x143f/0x4570 kernel/sched/core.c:6560
schedule+0xbf/0x180 kernel/sched/core.c:6636
schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1965
rcu_gp_fqs_loop+0x2d2/0x1150 kernel/rcu/tree.c:1706
rcu_gp_kthread+0xa3/0x3b0 kernel/rcu/tree.c:1905
kthread+0x28d/0x320 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:111 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:567


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 50cbba13faa2 Linux 6.1.159
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1290711a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=6a5cbd268406bf43
dashboard link: https://syzkaller.appspot.com/bug?extid=009b2a7f9d8a0615cf9b
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13eb9b2c580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/50ceb00b1b39/disk-50cbba13.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ebb8883b9a29/vmlinux-50cbba13.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7edc2a795f03/bzImage-50cbba13.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+009b2a...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 1-...D } 2690 jiffies s: 3673 root: 0x2/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4506 Comm: modprobe Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:check_preemption_disabled+0x1f/0x110 lib/smp_processor_id.c:16
Code: be 8a 48 c7 c6 00 f9 be 8a eb 00 55 41 57 41 56 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 08 65 8b 05 41 98 f1 75 <65> 8b 0d e2 ed f1 75 f7 c1 ff ff ff 7f 74 1f 65 48 8b 0c 25 28 00
RSP: 0018:ffffc900001e0cc8 EFLAGS: 00000082
RAX: 0000000000000001 RBX: ffff8880b8f2a6c8 RCX: 0000000000010000
RDX: ffff888027623b80 RSI: ffffffff8abef900 RDI: ffffffff8abef8c0
RBP: ffffc900001e0e88 R08: dffffc0000000000 R09: fffffbfff1bfe1c6
R10: fffffbfff1bfe1c6 R11: 1ffffffff1bfe1c5 R12: ffff88802c145340
R13: 0000000000000001 R14: 0000000000000001 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4fc48a1eb8 CR3: 0000000023836000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
rcu_dynticks_curr_cpu_in_eqs include/linux/context_tracking.h:122 [inline]
rcu_is_watching+0x11/0xa0 kernel/rcu/tree.c:721
trace_hrtimer_expire_exit include/trace/events/timer.h:286 [inline]
__run_hrtimer kernel/time/hrtimer.c:1750 [inline]
__hrtimer_run_queues+0x5fe/0xd60 kernel/time/hrtimer.c:1811
hrtimer_interrupt+0x3c5/0x9c0 kernel/time/hrtimer.c:1873
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
__sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:memset_erms+0xb/0x10 arch/x86/lib/memset_64.S:65
Code: 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 f3 aa <4c> 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 01 01
RSP: 0018:ffffc90003706f88 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffffc90003707068 RCX: 0000000000000000
RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffffc900037070c8
RBP: ffffffff8e87c01e R08: dffffc0000000000 R09: ffffc900037070b8
R10: fffff520006e0e19 R11: 1ffff920006e0e17 R12: 1ffff920006e0e0e
R13: dffffc0000000000 R14: ffffc900037070b8 R15: ffffc9000370709d
unwind_next_frame+0xb8a/0x20b0 arch/x86/kernel/unwind_orc.c:546
arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
__kasan_slab_alloc+0x6b/0x80 mm/kasan/common.c:328
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook+0x4b/0x480 mm/slab.h:737
kmem_cache_alloc_bulk+0x3ba/0x4e0 mm/slub.c:3880
mt_alloc_bulk lib/maple_tree.c:159 [inline]
mas_alloc_nodes+0x449/0x890 lib/maple_tree.c:1301
mas_node_count_gfp lib/maple_tree.c:1361 [inline]
mas_preallocate+0x161/0x3c0 lib/maple_tree.c:5809
__vma_adjust+0x2e2/0x1c60 mm/mmap.c:724
vma_adjust include/linux/mm.h:2810 [inline]
__split_vma+0x3a7/0x500 mm/mmap.c:-1
do_mas_align_munmap+0x762/0x1220 mm/mmap.c:2501
do_mas_munmap+0x240/0x2b0 mm/mmap.c:2650
__mmap_region mm/mmap.c:2698 [inline]
mmap_region+0x6e5/0x1c70 mm/mmap.c:2916
do_mmap+0x958/0xfd0 mm/mmap.c:1436
vm_mmap_pgoff+0x1b2/0x2b0 mm/util.c:520
ksys_mmap_pgoff+0x516/0x6f0 mm/mmap.c:1482
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4fc4b84242
Code: 08 00 04 00 00 eb e2 90 41 f7 c1 ff 0f 00 00 75 27 55 89 cd 53 48 89 fb 48 85 ff 74 33 41 89 ea 48 89 df b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 5e 5b 5d c3 0f 1f 00 c7 05 46 40 01 00 16 00
RSP: 002b:00007fff66d66008 EFLAGS: 00000206 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f4fc4889000 RCX: 00007f4fc4b84242
RDX: 0000000000000001 RSI: 0000000000008000 RDI: 00007f4fc4889000
RBP: 0000000000000812 R08: 0000000000000000 R09: 0000000000024000
R10: 0000000000000812 R11: 0000000000000206 R12: 00007fff66d66090
R13: 00007f4fc4b61ab0 R14: 00007fff66d66480 R15: 00000fffecdacc04
</TASK>


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