linux-kernel - [RFC PATCH v2 2/2] ARM/mm/fault: Enable interrupts before sending signal

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20251127140109.191657-2-xieyuanbin1@huawei.com>
Date: Thu, 27 Nov 2025 22:01:09 +0800
From: Xie Yuanbin <xieyuanbin1@...wei.com>
To: <viro@...iv.linux.org.uk>, <will@...nel.org>, <nico@...xnic.net>,
	<rmk+kernel@...linux.org.uk>, <linux@...linux.org.uk>,
	<david.laight@...box.com>, <rppt@...nel.org>, <vbabka@...e.cz>,
	<pfalcato@...e.de>, <brauner@...nel.org>, <lorenzo.stoakes@...cle.com>,
	<kuninori.morimoto.gx@...esas.com>, <tony@...mide.com>, <arnd@...db.de>,
	<bigeasy@...utronix.de>, <akpm@...ux-foundation.org>,
	<punitagrawal@...il.com>, <hch@....de>, <jack@...e.com>, <rjw@...ysocki.net>,
	<marc.zyngier@....com>
CC: <linux-arm-kernel@...ts.infradead.org>, <linux-mm@...ck.org>,
	<linux-kernel@...r.kernel.org>, <linux-fsdevel@...r.kernel.org>,
	<wozizhi@...weicloud.com>, <liaohua4@...wei.com>, <lilinjie8@...wei.com>,
	<xieyuanbin1@...wei.com>, <pangliyuan1@...wei.com>,
	<wangkefeng.wang@...wei.com>
Subject: [RFC PATCH v2 2/2] ARM/mm/fault: Enable interrupts before sending signal

From: xieyuanbin1 <xieyuanbin1@...wei.com>

Sending a signal requires to acquire sighand_struct::siglock which is a
spinlock_t. On PREEMPT_RT spinlock_t becomes a sleeping spin lock which
requires interrupts to be enabled. Since the calling context is user
land, interrupts must have been enabled so it is fine to enable them in
this case.

Signed-off-by: xieyuanbin1 <xieyuanbin1@...wei.com>
Cc: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
This patch depends on patch
Link: https://lore.kernel.org/20251029155918.503060-6-bigeasy@linutronix.de

The commit message is copy from:
Link: https://lore.kernel.org/20251029155918.503060-3-bigeasy@linutronix.de

Maybe I should add:
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Or something else? Thanks!

 arch/arm/mm/fault.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index 5c58072d8235..f8ee1854c854 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -184,10 +184,13 @@ __do_user_fault(unsigned long addr, unsigned int fsr, unsigned int sig,
 	struct task_struct *tsk = current;
 
 	if (addr > TASK_SIZE)
 		harden_branch_predictor();
 
+	if (IS_ENABLED(CONFIG_PREEMPT_RT))
+		local_irq_enable();
+
 #ifdef CONFIG_DEBUG_USER
 	if (((user_debug & UDBG_SEGV) && (sig == SIGSEGV)) ||
 	    ((user_debug & UDBG_BUS)  && (sig == SIGBUS))) {
 		pr_err("8<--- cut here ---\n");
 		pr_err("%s: unhandled page fault (%d) at 0x%08lx, code 0x%03x\n",
-- 
2.51.0