INFO: rcu detected stall in vma_expand (4)

Status: upstream: reported on 2026/07/29 12:00
Reported-by: syzbot+24ae7c2559dfdd55e23c@syzkaller.appspotmail.com
First crash: 72d, last: 6d03h
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 INFO: rcu detected stall in vma_expand origin:lts-only 1 syz error 1 152d 152d 0/2 upstream: reported syz repro on 2026/05/10 14:35
linux-6.1 INFO: rcu detected stall in vma_expand 1 1 1038d 1038d 0/3 auto-obsoleted due to no activity on 2024/03/15 20:47
upstream INFO: rcu detected stall in vma_expand mm 1 8 771d 887d 0/29 auto-obsoleted due to no activity on 2024/11/27 12:01
linux-6.1 INFO: rcu detected stall in vma_expand (3) 1 4 256d 436d 0/3 auto-obsoleted due to no activity on 2026/05/06 20:38
linux-6.1 INFO: rcu detected stall in vma_expand (2) 1 1 799d 799d 0/3 auto-obsoleted due to no activity on 2024/11/09 10:52

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 1-.... } 2648 jiffies s: 4565 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: 6041 Comm: syz.3.567 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__kasan_check_read+0x6/0x10 mm/kasan/shadow.c:31
Code: 41 5f 5d c3 48 c7 c7 c3 38 62 8c eb 0a 48 c7 c7 fe a6 46 8c 48 89 de e8 c8 e3 54 08 31 ed eb d7 00 00 cc cc 89 f6 48 8b 0c 24 <31> d2 e9 c3 ec ff ff 0f 1f 00 89 f6 48 8b 0c 24 ba 01 00 00 00 e9
RSP: 0018:ffffc900001e0370 EFLAGS: 00000046
RAX: ffffffff818ea1fa RBX: ffff8880b8f3bbb0 RCX: ffffffff818ea20b
RDX: 0000000000000100 RSI: 0000000000000004 RDI: ffff8880b8f3bbb8
RBP: 0000000000000001 R08: ffffffff8e20d96f R09: 1ffffffff1c41b2d
R10: dffffc0000000000 R11: fffffbfff1c41b2e R12: 0000000000000000
R13: dffffc0000000001 R14: ffff8880b8f3bbb8 R15: dffffc0000000000
FS:  0000555575f6c500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000040 CR3: 000000007d953000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 instrument_atomic_read include/linux/instrumented.h:72 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]
 __irq_work_queue_local+0x2b/0x190 kernel/irq_work.c:85
 irq_work_queue_on+0x13c/0x260 kernel/irq_work.c:165
 rcu_read_unlock_special+0x3c9/0x510 kernel/rcu/tree_plugin.h:678
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 trace_call_bpf+0x5bb/0x6b0 kernel/trace/bpf_trace.c:137
 perf_trace_run_bpf_submit+0x79/0x1c0 kernel/events/core.c:10037
 perf_trace_preemptirq_template+0x268/0x320 include/trace/events/preemptirq.h:14
 trace_irq_enable_rcuidle+0xd3/0x140 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x24/0x40 kernel/trace/trace_preemptirq.c:44
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728
RIP: 0010:rcu_read_unlock_special+0x7f/0x510 kernel/rcu/tree_plugin.h:685
Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 d2 68 95 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc900001e0840 EFLAGS: 00000206
RAX: 3687f0080d753600 RBX: 1ffff9200003c110 RCX: 3687f0080d753600
RDX: dffffc0000000000 RSI: ffffffff8a8c18a0 RDI: ffffffff8adf6de0
RBP: ffffc900001e0928 R08: ffffffff90b3331f R09: 1ffffffff2166663
R10: dffffc0000000000 R11: fffffbfff2166664 R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8f3bb00 R15: 0000000000000002
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 arp_xmit+0x20e/0x260 net/ipv4/arp.c:667
 arp_solicit+0xbef/0xe10 net/ipv4/arp.c:392
 neigh_probe net/core/neighbour.c:1080 [inline]
 neigh_timer_handler+0xaba/0x1090 net/core/neighbour.c:1162
 call_timer_fn+0x1ac/0x670 kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x56c/0x810 kernel/time/timer.c:2023
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036
 handle_softirqs+0x291/0x910 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 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:check_region_inline mm/kasan/generic.c:-1 [inline]
RIP: 0010:kasan_check_range+0xe/0x290 mm/kasan/generic.c:189
Code: 0f 0b b8 ea ff ff ff c3 0f 0b b8 ea ff ff ff c3 00 00 cc cc 00 00 cc cc 00 00 cc cc b0 01 48 85 f6 0f 84 ac 01 00 00 55 41 57 <41> 56 41 54 53 49 89 f8 49 01 f0 0f 82 0e 02 00 00 49 89 f8 49 c1
RSP: 0018:ffffc90004e0f148 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000010 RCX: ffffffff8139037a
RDX: 0000000000000001 RSI: 0000000000000010 RDI: ffffc90004e0f278
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000006
R10: dffffc0000000000 R11: fffff520009c1e51 R12: dffffc0000000000
R13: ffffc90004e10000 R14: ffffc90004e0f278 R15: ffffc90004e0f25d
 memset+0x1e/0x40 mm/kasan/shadow.c:44
 unwind_next_frame+0x8da/0x1fd0 arch/x86/kernel/unwind_orc.c:546
 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:516
 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1729 [inline]
 slab_free_freelist_hook+0x133/0x1b0 mm/slub.c:1755
 slab_free mm/slub.c:3687 [inline]
 kmem_cache_free+0xf7/0x2a0 mm/slub.c:3709
 mas_destroy+0x2542/0x2d40 lib/maple_tree.c:5867
 mas_store_prealloc+0x32c/0x430 lib/maple_tree.c:5792
 vma_expand+0x57d/0x850 mm/mmap.c:570
 __mmap_region mm/mmap.c:2740 [inline]
 mmap_region+0xc69/0x1c50 mm/mmap.c:2916
 do_mmap+0x9ce/0x10d0 mm/mmap.c:1436
 vm_mmap_pgoff+0x1c1/0x2d0 mm/util.c:520
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f709bf9dec2
Code: 4f 01 00 0f 1f 44 00 00 41 f7 c1 ff 0f 00 00 75 27 55 89 cd 53 48 89 fb 48 85 ff 74 3b 41 89 ea 48 89 df b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 6e 5b 5d c3 0f 1f 00 48 c7 c0 e8 ff ff ff 64
RSP: 002b:00007ffdc05893e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f709bf9dec2
RDX: 0000000000000000 RSI: 0000000000021000 RDI: 0000000000000000
RBP: 0000000000020022 R08: 00000000ffffffff R09: 0000000000000000
R10: 0000000000020022 R11: 0000000000000246 R12: 00007ffdc0589550
R13: ffffffffffffffc0 R14: 0000000000001000 R15: 0000000000000000
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/03 23:08 linux-6.1.y a500ba24937a 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in vma_expand
2026/08/22 12:41 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in vma_expand
2026/07/29 11:59 linux-6.1.y dc5c83b7f5f8 19622d9d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in vma_expand
* Struck through repros no longer work on HEAD.