From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from server.eikel.org (server.eikel.org [178.77.101.203]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0D491371875 for ; Mon, 16 Mar 2026 08:24:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=178.77.101.203 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773649486; cv=none; b=H8JtNATVOfe9UEEk6xpRrIN5jXDbWZCeJ0aeFNsruEJi0fcixdt3vbntH1ckpQ3CCb0C/pkHMsec+U+E6e4kAyV1J9hXtLSYak1WUAf6qcQUglbA+BgaDM75TcQ6xMdvnR7MSYCpkZ+IgRI/Wl9btiUhX1mjNqCEsB0WD1MRncI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773649486; c=relaxed/simple; bh=dPQW9WeWEPuEQhM49ZwwIL/lc0RifueYXeJ4VOOsMdw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=tajqXvHoe7LeZCaD1zpoe7DJAEQzgSGsveROuDDXDq5hHnhn6vRGuhwHW8vq8AQcL3dYn6rnxRxRketCN/IbHDFhjqQJ1DLJQKjJxOaFMuB2YrQrx7S6qGqd9WpihjNFP0d8THLShDX31jXvAVdBNmwraoAgblLfLiCaGGzYglM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=eikel.org; spf=fail smtp.mailfrom=eikel.org; dkim=pass (1024-bit key) header.d=eikel.org header.i=@eikel.org header.b=G0n9kX3c; arc=none smtp.client-ip=178.77.101.203 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=eikel.org Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=eikel.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=eikel.org header.i=@eikel.org header.b="G0n9kX3c" Received: from thinkpad-benjamin.localnet (unknown [80.87.119.134]) by server.eikel.org (Postfix) with ESMTPSA id B265A1F84F; Mon, 16 Mar 2026 09:18:38 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=eikel.org; s=default; t=1773649118; bh=wGBVXe2TB5XgCdAAUbnS3K46JlvHZt+p4uQTs/+CRRA=; h=From:To:Subject; b=G0n9kX3cxQQy2NJ8EecYeuOS9vpXQLTM3n7KXFDeNHE0zxdyfe49CgsYPPTFUtIiT AIrLdWm1v3qGDXF2rH/yZINF9lYM5Ft0O+gw0AdNM4u+sljN40OrCp4N83v5/RmQxv dzgmjYLM2msXrijW3KO4utH2oeEvZg9ZRmG8TKeU= Authentication-Results: server.eikel.org; spf=pass (sender IP is 80.87.119.134) smtp.mailfrom=debian@eikel.org smtp.helo=thinkpad-benjamin.localnet Received-SPF: pass (server.eikel.org: connection is authenticated) From: Benjamin Eikel 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 Message-ID: <6261958.lOV4Wx5bFT@thinkpad-benjamin> Precedence: bulk X-Mailing-List: rcu@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Dear Linux kernel developers, I have reported this issue as Debian bug #1130138 [1], which has been marke= d=20 =E2=80=9Cupstream=E2=80=9D. I am therefore also reaching out here to make y= ou aware of it.=20 Please let me know if you need additional information. After upgrading from linux-image-6.18.15+deb14-amd64, I see this error seve= ral=20 times and the system shortly freezes. It seems related to Zoom crashing fir= st,=20 but the freezes were not noticable with older Linux kernels. Currently booted into 6.18.15+deb14-amd64 which does not exhibit this issue= =2E=20 The stalls occurred when running 6.19.6+deb14-amd64. More information about= my=20 system can be found in the Debian bug report. M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: rcu: INFO: rcu_preempt detec= ted=20 stalls on CPUs/tasks: M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: rcu: Tasks blocked o= n=20 level-0 rcu_node (CPUs 0-15): P10008/1:b..l M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: rcu: (detected by 5,= t=3D5252=20 jiffies, g=3D177537, q=3D28067 ncpus=3D16) M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: task:zoom state:R= =20 running task stack:0 pid:10008 tgid:10008 ppid:2089 =20 task_flags:0x40040c flags:0x00080802 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: Call Trace: M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: __schedule+0x48a/0xfc0 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: preempt_schedule+0x32/0x50 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: preempt_schedule_thunk+0x16= /0x30 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: _raw_spin_unlock+0x22/0x30 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: unmap_page_range+0xbcb/0x17= 00 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: unmap_vmas+0xa1/0x180 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: exit_mmap+0xe1/0x3b0 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: __mmput+0x41/0x150 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: do_exit+0x251/0xa70 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: do_group_exit+0x2d/0xc0 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: ?=20 srso_alias_return_thunk+0x5/0xfbef5 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: get_signal+0x8a4/0x920 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: =20 arch_do_signal_or_restart+0x40/0x250 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: exit_to_user_mode_loop+0x8e= /0x480 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: ? __x64_sys_sched_setaffini= ty+0x6a/ 0xb0 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: do_syscall_64+0x20b/0x600 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: ?=20 srso_alias_return_thunk+0x5/0xfbef5 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: ? ksys_read+0xcd/0xf0 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: ?=20 srso_alias_return_thunk+0x5/0xfbef5 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: ? do_syscall_64+0xbe/0x600 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: ?=20 srso_alias_return_thunk+0x5/0xfbef5 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: ? do_syscall_64+0xbe/0x600 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: ? __x64_sys_close+0x3d/0x80 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: ?=20 srso_alias_return_thunk+0x5/0xfbef5 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: ? do_syscall_64+0xbe/0x600 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: ?=20 srso_alias_return_thunk+0x5/0xfbef5 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: ? exc_page_fault+0x7e/0x1a0 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: =20 entry_SYSCALL_64_after_hwframe+0x76/0x7e M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: RIP: 0033:0x7f2876359e2d M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: RSP: 002b:00007ffc91243ad8 E= =46LAGS:=20 00000246 ORIG_RAX: 00000000000000cb M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: RAX: 0000000000000000 RBX:=20 00007f2875207700 RCX: 00007f2876359e2d M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: RDX: 00007ffc91243ae0 RSI:=20 0000000000000080 RDI: 0000000000002718 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: RBP: 0000000000000020 R08:=20 0000000000000001 R09: 00007f2875206de8 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: R10: 0000000000000000 R11:=20 0000000000000246 R12: 00007ffc91243ae0 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: R13: 00007ffc91243c80 R14:=20 0000000000000000 R15: 0000000000000020 M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: rcu: INFO: rcu_preempt detec= ted=20 expedited stalls on CPUs/tasks: { P10008 } 5361 jiffies s: 1609 root: 0x0/T M=C3=A4r 09 09:13:48 thinkpad-benjamin kernel: rcu: blocking rcu_node struc= tures=20 (internal RCU debug): Another one: M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: rcu: INFO: rcu_preempt detec= ted=20 stalls on CPUs/tasks: M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: rcu: Tasks blocked o= n=20 level-0 rcu_node (CPUs 0-15): P10008/1:b..l M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: rcu: (detected by 5,= t=3D21007=20 jiffies, g=3D177537, q=3D87903 ncpus=3D16) M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: task:zoom state:R= =20 running task stack:0 pid:10008 tgid:10008 ppid:2089 =20 task_flags:0x40040c flags:0x00080802 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: Call Trace: M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: __schedule+0x48a/0xfc0 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: preempt_schedule+0x32/0x50 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: preempt_schedule_thunk+0x16= /0x30 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: _raw_spin_unlock+0x22/0x30 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: unmap_page_range+0xbcb/0x17= 00 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: unmap_vmas+0xa1/0x180 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: exit_mmap+0xe1/0x3b0 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: __mmput+0x41/0x150 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: do_exit+0x251/0xa70 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: do_group_exit+0x2d/0xc0 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: ?=20 srso_alias_return_thunk+0x5/0xfbef5 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: get_signal+0x8a4/0x920 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: =20 arch_do_signal_or_restart+0x40/0x250 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: exit_to_user_mode_loop+0x8e= /0x480 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: ? __x64_sys_sched_setaffini= ty+0x6a/ 0xb0 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: do_syscall_64+0x20b/0x600 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: ?=20 srso_alias_return_thunk+0x5/0xfbef5 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: ? ksys_read+0xcd/0xf0 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: ?=20 srso_alias_return_thunk+0x5/0xfbef5 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: ? do_syscall_64+0xbe/0x600 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: ?=20 srso_alias_return_thunk+0x5/0xfbef5 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: ? do_syscall_64+0xbe/0x600 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: ? __x64_sys_close+0x3d/0x80 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: ?=20 srso_alias_return_thunk+0x5/0xfbef5 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: ? do_syscall_64+0xbe/0x600 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: ?=20 srso_alias_return_thunk+0x5/0xfbef5 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: ? exc_page_fault+0x7e/0x1a0 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: =20 entry_SYSCALL_64_after_hwframe+0x76/0x7e M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: RIP: 0033:0x7f2876359e2d M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: RSP: 002b:00007ffc91243ad8 E= =46LAGS:=20 00000246 ORIG_RAX: 00000000000000cb M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: RAX: 0000000000000000 RBX:=20 00007f2875207700 RCX: 00007f2876359e2d M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: RDX: 00007ffc91243ae0 RSI:=20 0000000000000080 RDI: 0000000000002718 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: RBP: 0000000000000020 R08:=20 0000000000000001 R09: 00007f2875206de8 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: R10: 0000000000000000 R11:=20 0000000000000246 R12: 00007ffc91243ae0 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: R13: 00007ffc91243c80 R14:=20 0000000000000000 R15: 0000000000000020 M=C3=A4r 09 09:14:51 thinkpad-benjamin kernel: M=C3=A4r 09 09:14:52 thinkpad-benjamin kernel: rcu: INFO: rcu_preempt detec= ted=20 expedited stalls on CPUs/tasks: { P10008 } 21233 jiffies s: 1609 root: 0x0/T M=C3=A4r 09 09:14:52 thinkpad-benjamin kernel: rcu: blocking rcu_node struc= tures=20 (internal RCU debug): Note the stall duration escalating from t=3D5252 jiffies (~5s) to t=3D21007= jiffies=20 (~21s), with the same grace period (g=3D177537), indicating the unmap_page_= range=20 operation blocked for over a minute. Kind regards Benjamin [1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=3D1130138