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  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]
Date:   Mon, 24 Jan 2022 18:47:36 +0100
From:   Ard Biesheuvel <>
Cc:, Ard Biesheuvel <>,
        Nicolas Pitre <>,
        Arnd Bergmann <>,
        Kees Cook <>,
        Keith Packard <>,
        Linus Walleij <>,
        Nick Desaulniers <>,
        Tony Lindgren <>,
        Marc Zyngier <>,
        Vladimir Murzin <>,
        Jesse Taube <>
Subject: [PATCH v5 24/32] ARM: run softirqs on the per-CPU IRQ stack

Now that we have enabled IRQ stacks, any softIRQs that are handled over
the back of a hard IRQ will run from the IRQ stack as well. However, any
synchronous softirq processing that happens when re-enabling softIRQs
from task context will still execute on that task's stack.

Since any call to local_bh_enable() at any level in the task's call
stack may trigger a softIRQ processing run, which could potentially
cause a task stack overflow if the combined stack footprints exceed the
stack's size, let's run these synchronous invocations of do_softirq() on
the IRQ stack as well.

Signed-off-by: Ard Biesheuvel <>
Reviewed-by: Arnd Bergmann <>
Acked-by: Linus Walleij <>
Tested-by: Keith Packard <>
Tested-by: Marc Zyngier <>
Tested-by: Vladimir Murzin <> # ARMv7M
 arch/arm/Kconfig      |  2 ++
 arch/arm/kernel/irq.c | 14 ++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 108a7a872084..b959249dd716 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -128,6 +128,8 @@ config ARM
 	select RTC_LIB
 	# Above selects are sorted alphabetically; please add new ones
 	# according to that.  Thanks.
diff --git a/arch/arm/kernel/irq.c b/arch/arm/kernel/irq.c
index 92ae80a8e5b4..380376f55554 100644
--- a/arch/arm/kernel/irq.c
+++ b/arch/arm/kernel/irq.c
@@ -36,11 +36,14 @@
 #include <asm/hardware/cache-l2x0.h>
 #include <asm/hardware/cache-uniphier.h>
 #include <asm/outercache.h>
+#include <asm/softirq_stack.h>
 #include <asm/exception.h>
 #include <asm/mach/arch.h>
 #include <asm/mach/irq.h>
 #include <asm/mach/time.h>
+#include "reboot.h"
 unsigned long irq_err_count;
 asmlinkage DEFINE_PER_CPU_READ_MOSTLY(u8 *, irq_stack_ptr);
@@ -58,6 +61,17 @@ static void __init init_irq_stacks(void)
+static void ____do_softirq(void *arg)
+	__do_softirq();
+void do_softirq_own_stack(void)
+	call_with_stack(____do_softirq, NULL,
+			__this_cpu_read(irq_stack_ptr));
 int arch_show_interrupts(struct seq_file *p, int prec)
 #ifdef CONFIG_FIQ

Powered by blists - more mailing lists