From: Benjamin Eikel <debian@eikel.org>
To: linux-mm@kvack.org
Cc: rcu@vger.kernel.org
Subject: [BUG] RCU stall in unmap_page_range during exit_mmap (6.19 regression)
Date: Mon, 16 Mar 2026 09:18:37 +0100 [thread overview]
Message-ID: <6261958.lOV4Wx5bFT@thinkpad-benjamin> (raw)
Dear Linux kernel developers,
I have reported this issue as Debian bug #1130138 [1], which has been marked
“upstream”. I am therefore also reaching out here to make you aware of it.
Please let me know if you need additional information.
After upgrading from linux-image-6.18.15+deb14-amd64, I see this error several
times and the system shortly freezes. It seems related to Zoom crashing first,
but the freezes were not noticable with older Linux kernels.
Currently booted into 6.18.15+deb14-amd64 which does not exhibit this issue.
The stalls occurred when running 6.19.6+deb14-amd64. More information about my
system can be found in the Debian bug report.
Mär 09 09:13:48 thinkpad-benjamin kernel: rcu: INFO: rcu_preempt detected
stalls on CPUs/tasks:
Mär 09 09:13:48 thinkpad-benjamin kernel: rcu: Tasks blocked on
level-0 rcu_node (CPUs 0-15): P10008/1:b..l
Mär 09 09:13:48 thinkpad-benjamin kernel: rcu: (detected by 5, t=5252
jiffies, g=177537, q=28067 ncpus=16)
Mär 09 09:13:48 thinkpad-benjamin kernel: task:zoom state:R
running task stack:0 pid:10008 tgid:10008 ppid:2089
task_flags:0x40040c flags:0x00080802
Mär 09 09:13:48 thinkpad-benjamin kernel: Call Trace:
Mär 09 09:13:48 thinkpad-benjamin kernel: <TASK>
Mär 09 09:13:48 thinkpad-benjamin kernel: __schedule+0x48a/0xfc0
Mär 09 09:13:48 thinkpad-benjamin kernel: preempt_schedule+0x32/0x50
Mär 09 09:13:48 thinkpad-benjamin kernel: preempt_schedule_thunk+0x16/0x30
Mär 09 09:13:48 thinkpad-benjamin kernel: _raw_spin_unlock+0x22/0x30
Mär 09 09:13:48 thinkpad-benjamin kernel: unmap_page_range+0xbcb/0x1700
Mär 09 09:13:48 thinkpad-benjamin kernel: unmap_vmas+0xa1/0x180
Mär 09 09:13:48 thinkpad-benjamin kernel: exit_mmap+0xe1/0x3b0
Mär 09 09:13:48 thinkpad-benjamin kernel: __mmput+0x41/0x150
Mär 09 09:13:48 thinkpad-benjamin kernel: do_exit+0x251/0xa70
Mär 09 09:13:48 thinkpad-benjamin kernel: do_group_exit+0x2d/0xc0
Mär 09 09:13:48 thinkpad-benjamin kernel: ?
srso_alias_return_thunk+0x5/0xfbef5
Mär 09 09:13:48 thinkpad-benjamin kernel: get_signal+0x8a4/0x920
Mär 09 09:13:48 thinkpad-benjamin kernel:
arch_do_signal_or_restart+0x40/0x250
Mär 09 09:13:48 thinkpad-benjamin kernel: exit_to_user_mode_loop+0x8e/0x480
Mär 09 09:13:48 thinkpad-benjamin kernel: ? __x64_sys_sched_setaffinity+0x6a/
0xb0
Mär 09 09:13:48 thinkpad-benjamin kernel: do_syscall_64+0x20b/0x600
Mär 09 09:13:48 thinkpad-benjamin kernel: ?
srso_alias_return_thunk+0x5/0xfbef5
Mär 09 09:13:48 thinkpad-benjamin kernel: ? ksys_read+0xcd/0xf0
Mär 09 09:13:48 thinkpad-benjamin kernel: ?
srso_alias_return_thunk+0x5/0xfbef5
Mär 09 09:13:48 thinkpad-benjamin kernel: ? do_syscall_64+0xbe/0x600
Mär 09 09:13:48 thinkpad-benjamin kernel: ?
srso_alias_return_thunk+0x5/0xfbef5
Mär 09 09:13:48 thinkpad-benjamin kernel: ? do_syscall_64+0xbe/0x600
Mär 09 09:13:48 thinkpad-benjamin kernel: ? __x64_sys_close+0x3d/0x80
Mär 09 09:13:48 thinkpad-benjamin kernel: ?
srso_alias_return_thunk+0x5/0xfbef5
Mär 09 09:13:48 thinkpad-benjamin kernel: ? do_syscall_64+0xbe/0x600
Mär 09 09:13:48 thinkpad-benjamin kernel: ?
srso_alias_return_thunk+0x5/0xfbef5
Mär 09 09:13:48 thinkpad-benjamin kernel: ? exc_page_fault+0x7e/0x1a0
Mär 09 09:13:48 thinkpad-benjamin kernel:
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Mär 09 09:13:48 thinkpad-benjamin kernel: RIP: 0033:0x7f2876359e2d
Mär 09 09:13:48 thinkpad-benjamin kernel: RSP: 002b:00007ffc91243ad8 EFLAGS:
00000246 ORIG_RAX: 00000000000000cb
Mär 09 09:13:48 thinkpad-benjamin kernel: RAX: 0000000000000000 RBX:
00007f2875207700 RCX: 00007f2876359e2d
Mär 09 09:13:48 thinkpad-benjamin kernel: RDX: 00007ffc91243ae0 RSI:
0000000000000080 RDI: 0000000000002718
Mär 09 09:13:48 thinkpad-benjamin kernel: RBP: 0000000000000020 R08:
0000000000000001 R09: 00007f2875206de8
Mär 09 09:13:48 thinkpad-benjamin kernel: R10: 0000000000000000 R11:
0000000000000246 R12: 00007ffc91243ae0
Mär 09 09:13:48 thinkpad-benjamin kernel: R13: 00007ffc91243c80 R14:
0000000000000000 R15: 0000000000000020
Mär 09 09:13:48 thinkpad-benjamin kernel: </TASK>
Mär 09 09:13:48 thinkpad-benjamin kernel: rcu: INFO: rcu_preempt detected
expedited stalls on CPUs/tasks: { P10008 } 5361 jiffies s: 1609 root: 0x0/T
Mär 09 09:13:48 thinkpad-benjamin kernel: rcu: blocking rcu_node structures
(internal RCU debug):
Another one:
Mär 09 09:14:51 thinkpad-benjamin kernel: rcu: INFO: rcu_preempt detected
stalls on CPUs/tasks:
Mär 09 09:14:51 thinkpad-benjamin kernel: rcu: Tasks blocked on
level-0 rcu_node (CPUs 0-15): P10008/1:b..l
Mär 09 09:14:51 thinkpad-benjamin kernel: rcu: (detected by 5, t=21007
jiffies, g=177537, q=87903 ncpus=16)
Mär 09 09:14:51 thinkpad-benjamin kernel: task:zoom state:R
running task stack:0 pid:10008 tgid:10008 ppid:2089
task_flags:0x40040c flags:0x00080802
Mär 09 09:14:51 thinkpad-benjamin kernel: Call Trace:
Mär 09 09:14:51 thinkpad-benjamin kernel: <TASK>
Mär 09 09:14:51 thinkpad-benjamin kernel: __schedule+0x48a/0xfc0
Mär 09 09:14:51 thinkpad-benjamin kernel: preempt_schedule+0x32/0x50
Mär 09 09:14:51 thinkpad-benjamin kernel: preempt_schedule_thunk+0x16/0x30
Mär 09 09:14:51 thinkpad-benjamin kernel: _raw_spin_unlock+0x22/0x30
Mär 09 09:14:51 thinkpad-benjamin kernel: unmap_page_range+0xbcb/0x1700
Mär 09 09:14:51 thinkpad-benjamin kernel: unmap_vmas+0xa1/0x180
Mär 09 09:14:51 thinkpad-benjamin kernel: exit_mmap+0xe1/0x3b0
Mär 09 09:14:51 thinkpad-benjamin kernel: __mmput+0x41/0x150
Mär 09 09:14:51 thinkpad-benjamin kernel: do_exit+0x251/0xa70
Mär 09 09:14:51 thinkpad-benjamin kernel: do_group_exit+0x2d/0xc0
Mär 09 09:14:51 thinkpad-benjamin kernel: ?
srso_alias_return_thunk+0x5/0xfbef5
Mär 09 09:14:51 thinkpad-benjamin kernel: get_signal+0x8a4/0x920
Mär 09 09:14:51 thinkpad-benjamin kernel:
arch_do_signal_or_restart+0x40/0x250
Mär 09 09:14:51 thinkpad-benjamin kernel: exit_to_user_mode_loop+0x8e/0x480
Mär 09 09:14:51 thinkpad-benjamin kernel: ? __x64_sys_sched_setaffinity+0x6a/
0xb0
Mär 09 09:14:51 thinkpad-benjamin kernel: do_syscall_64+0x20b/0x600
Mär 09 09:14:51 thinkpad-benjamin kernel: ?
srso_alias_return_thunk+0x5/0xfbef5
Mär 09 09:14:51 thinkpad-benjamin kernel: ? ksys_read+0xcd/0xf0
Mär 09 09:14:51 thinkpad-benjamin kernel: ?
srso_alias_return_thunk+0x5/0xfbef5
Mär 09 09:14:51 thinkpad-benjamin kernel: ? do_syscall_64+0xbe/0x600
Mär 09 09:14:51 thinkpad-benjamin kernel: ?
srso_alias_return_thunk+0x5/0xfbef5
Mär 09 09:14:51 thinkpad-benjamin kernel: ? do_syscall_64+0xbe/0x600
Mär 09 09:14:51 thinkpad-benjamin kernel: ? __x64_sys_close+0x3d/0x80
Mär 09 09:14:51 thinkpad-benjamin kernel: ?
srso_alias_return_thunk+0x5/0xfbef5
Mär 09 09:14:51 thinkpad-benjamin kernel: ? do_syscall_64+0xbe/0x600
Mär 09 09:14:51 thinkpad-benjamin kernel: ?
srso_alias_return_thunk+0x5/0xfbef5
Mär 09 09:14:51 thinkpad-benjamin kernel: ? exc_page_fault+0x7e/0x1a0
Mär 09 09:14:51 thinkpad-benjamin kernel:
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Mär 09 09:14:51 thinkpad-benjamin kernel: RIP: 0033:0x7f2876359e2d
Mär 09 09:14:51 thinkpad-benjamin kernel: RSP: 002b:00007ffc91243ad8 EFLAGS:
00000246 ORIG_RAX: 00000000000000cb
Mär 09 09:14:51 thinkpad-benjamin kernel: RAX: 0000000000000000 RBX:
00007f2875207700 RCX: 00007f2876359e2d
Mär 09 09:14:51 thinkpad-benjamin kernel: RDX: 00007ffc91243ae0 RSI:
0000000000000080 RDI: 0000000000002718
Mär 09 09:14:51 thinkpad-benjamin kernel: RBP: 0000000000000020 R08:
0000000000000001 R09: 00007f2875206de8
Mär 09 09:14:51 thinkpad-benjamin kernel: R10: 0000000000000000 R11:
0000000000000246 R12: 00007ffc91243ae0
Mär 09 09:14:51 thinkpad-benjamin kernel: R13: 00007ffc91243c80 R14:
0000000000000000 R15: 0000000000000020
Mär 09 09:14:51 thinkpad-benjamin kernel: </TASK>
Mär 09 09:14:52 thinkpad-benjamin kernel: rcu: INFO: rcu_preempt detected
expedited stalls on CPUs/tasks: { P10008 } 21233 jiffies s: 1609 root: 0x0/T
Mär 09 09:14:52 thinkpad-benjamin kernel: rcu: blocking rcu_node structures
(internal RCU debug):
Note the stall duration escalating from t=5252 jiffies (~5s) to t=21007 jiffies
(~21s), with the same grace period (g=177537), indicating the unmap_page_range
operation blocked for over a minute.
Kind regards
Benjamin
[1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1130138
next reply other threads:[~2026-03-16 8:18 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-16 8:18 Benjamin Eikel [this message]
2026-03-17 14:46 ` [regression] Re: RCU stall in unmap_page_range during exit_mmap (6.19 regression) Thorsten Leemhuis
2026-03-17 16:19 ` [BUG] " Pedro Falcato
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