* [PATCH] LoongArch: Fix bitflag conflict for TIF_FIXADE
@ 2025-09-19 12:58 Yao Zi
2025-09-19 13:21 ` Wentao Guan
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Yao Zi @ 2025-09-19 12:58 UTC (permalink / raw)
To: Huacai Chen, WANG Xuerui, Thomas Huth, Yao Zi, Thomas Gleixner,
Xi Ruoyao
Cc: loongarch, linux-kernel
After LoongArch was converted to use the generic TIF bits in commit
f9629891d407 ("loongarch: Use generic TIF bits"), its TIF_FIXADE flag
takes the same bit with TIF_RESTORE_SIGMASK in thread_info.flags.
Such conflict causes TIF_FIXADE being considered cleared when
TIF_RESTORE_SIGMASK is cleared during deliver of a signal. And since
TIF_FIXADE determines whether unaligned access emulation works for a
task, userspace making use of unaligned access will receive unexpected
SIGBUS (and likely terminate) after receiving its first signal.
This conflict looks like a simple typo, let's just switch to a free bit.
Fixes: f9629891d407 ("loongarch: Use generic TIF bits")
Signed-off-by: Yao Zi <ziyao@disroot.org>
---
Note the problematic commit is contained in next-20250918, but not
master.
arch/loongarch/include/asm/thread_info.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/loongarch/include/asm/thread_info.h b/arch/loongarch/include/asm/thread_info.h
index def7cb14467e..4d7117fcdc78 100644
--- a/arch/loongarch/include/asm/thread_info.h
+++ b/arch/loongarch/include/asm/thread_info.h
@@ -77,7 +77,7 @@ register unsigned long current_stack_pointer __asm__("$sp");
#define TIF_NOHZ 16 /* in adaptive nohz mode */
#define TIF_USEDFPU 17 /* FPU was used by this task this quantum (SMP) */
#define TIF_USEDSIMD 18 /* SIMD has been used this quantum */
-#define TIF_FIXADE 10 /* Fix address errors in software */
+#define TIF_FIXADE 19 /* Fix address errors in software */
#define TIF_LOGADE 20 /* Log address errors to syslog */
#define TIF_32BIT_REGS 21 /* 32-bit general purpose registers */
#define TIF_32BIT_ADDR 22 /* 32-bit address space */
--
2.50.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re:[PATCH] LoongArch: Fix bitflag conflict for TIF_FIXADE
2025-09-19 12:58 [PATCH] LoongArch: Fix bitflag conflict for TIF_FIXADE Yao Zi
@ 2025-09-19 13:21 ` Wentao Guan
2025-09-20 4:16 ` [PATCH] " Huacai Chen
2025-09-20 8:25 ` [tip: core/core] " tip-bot2 for Yao Zi
2 siblings, 0 replies; 4+ messages in thread
From: Wentao Guan @ 2025-09-19 13:21 UTC (permalink / raw)
To: chenhuacai, WANG Xuerui, Thomas Huth, Yao Zi, tglx, Xi Ruoyao
Cc: loongarch, linux-kernel
Hello,
nice catch:)
Reviewed-by: Wentao Guan <guanwentao@uniontech.com>
BRs
Wentao Guan
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] LoongArch: Fix bitflag conflict for TIF_FIXADE
2025-09-19 12:58 [PATCH] LoongArch: Fix bitflag conflict for TIF_FIXADE Yao Zi
2025-09-19 13:21 ` Wentao Guan
@ 2025-09-20 4:16 ` Huacai Chen
2025-09-20 8:25 ` [tip: core/core] " tip-bot2 for Yao Zi
2 siblings, 0 replies; 4+ messages in thread
From: Huacai Chen @ 2025-09-20 4:16 UTC (permalink / raw)
To: Yao Zi
Cc: WANG Xuerui, Thomas Huth, Thomas Gleixner, Xi Ruoyao, loongarch,
linux-kernel
On Fri, Sep 19, 2025 at 8:58 PM Yao Zi <ziyao@disroot.org> wrote:
>
> After LoongArch was converted to use the generic TIF bits in commit
> f9629891d407 ("loongarch: Use generic TIF bits"), its TIF_FIXADE flag
> takes the same bit with TIF_RESTORE_SIGMASK in thread_info.flags.
>
> Such conflict causes TIF_FIXADE being considered cleared when
> TIF_RESTORE_SIGMASK is cleared during deliver of a signal. And since
> TIF_FIXADE determines whether unaligned access emulation works for a
> task, userspace making use of unaligned access will receive unexpected
> SIGBUS (and likely terminate) after receiving its first signal.
>
> This conflict looks like a simple typo, let's just switch to a free bit.
>
> Fixes: f9629891d407 ("loongarch: Use generic TIF bits")
> Signed-off-by: Yao Zi <ziyao@disroot.org>
> ---
>
> Note the problematic commit is contained in next-20250918, but not
> master.
It will be more beautiful if this patch is squashed to the original one.
Huacai
>
> arch/loongarch/include/asm/thread_info.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/loongarch/include/asm/thread_info.h b/arch/loongarch/include/asm/thread_info.h
> index def7cb14467e..4d7117fcdc78 100644
> --- a/arch/loongarch/include/asm/thread_info.h
> +++ b/arch/loongarch/include/asm/thread_info.h
> @@ -77,7 +77,7 @@ register unsigned long current_stack_pointer __asm__("$sp");
> #define TIF_NOHZ 16 /* in adaptive nohz mode */
> #define TIF_USEDFPU 17 /* FPU was used by this task this quantum (SMP) */
> #define TIF_USEDSIMD 18 /* SIMD has been used this quantum */
> -#define TIF_FIXADE 10 /* Fix address errors in software */
> +#define TIF_FIXADE 19 /* Fix address errors in software */
> #define TIF_LOGADE 20 /* Log address errors to syslog */
> #define TIF_32BIT_REGS 21 /* 32-bit general purpose registers */
> #define TIF_32BIT_ADDR 22 /* 32-bit address space */
> --
> 2.50.1
>
^ permalink raw reply [flat|nested] 4+ messages in thread* [tip: core/core] LoongArch: Fix bitflag conflict for TIF_FIXADE
2025-09-19 12:58 [PATCH] LoongArch: Fix bitflag conflict for TIF_FIXADE Yao Zi
2025-09-19 13:21 ` Wentao Guan
2025-09-20 4:16 ` [PATCH] " Huacai Chen
@ 2025-09-20 8:25 ` tip-bot2 for Yao Zi
2 siblings, 0 replies; 4+ messages in thread
From: tip-bot2 for Yao Zi @ 2025-09-20 8:25 UTC (permalink / raw)
To: linux-tip-commits; +Cc: Yao Zi, Thomas Gleixner, Wentao Guan, x86, linux-kernel
The following commit has been merged into the core/core branch of tip:
Commit-ID: 3ec09344b01a15901ba824e877a0562ed8103e27
Gitweb: https://git.kernel.org/tip/3ec09344b01a15901ba824e877a0562ed8103e27
Author: Yao Zi <ziyao@disroot.org>
AuthorDate: Fri, 19 Sep 2025 12:58:29
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Sat, 20 Sep 2025 09:55:56 +02:00
LoongArch: Fix bitflag conflict for TIF_FIXADE
After LoongArch was converted to use the generic TIF bits in commit
f9629891d407 ("loongarch: Use generic TIF bits"), its TIF_FIXADE flag
takes the same bit with TIF_RESTORE_SIGMASK in thread_info.flags.
Such conflict causes TIF_FIXADE being considered cleared when
TIF_RESTORE_SIGMASK is cleared during deliver of a signal. And since
TIF_FIXADE determines whether unaligned access emulation works for a
task, userspace making use of unaligned access will receive unexpected
SIGBUS (and likely terminate) after receiving its first signal.
This conflict looks like a simple typo, switch it to the free bit 19.
Fixes: f9629891d407 ("loongarch: Use generic TIF bits")
Signed-off-by: Yao Zi <ziyao@disroot.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Wentao Guan <guanwentao@uniontech.com>
---
arch/loongarch/include/asm/thread_info.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/loongarch/include/asm/thread_info.h b/arch/loongarch/include/asm/thread_info.h
index def7cb1..4d7117f 100644
--- a/arch/loongarch/include/asm/thread_info.h
+++ b/arch/loongarch/include/asm/thread_info.h
@@ -77,7 +77,7 @@ register unsigned long current_stack_pointer __asm__("$sp");
#define TIF_NOHZ 16 /* in adaptive nohz mode */
#define TIF_USEDFPU 17 /* FPU was used by this task this quantum (SMP) */
#define TIF_USEDSIMD 18 /* SIMD has been used this quantum */
-#define TIF_FIXADE 10 /* Fix address errors in software */
+#define TIF_FIXADE 19 /* Fix address errors in software */
#define TIF_LOGADE 20 /* Log address errors to syslog */
#define TIF_32BIT_REGS 21 /* 32-bit general purpose registers */
#define TIF_32BIT_ADDR 22 /* 32-bit address space */
^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2025-09-20 8:26 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2025-09-19 12:58 [PATCH] LoongArch: Fix bitflag conflict for TIF_FIXADE Yao Zi
2025-09-19 13:21 ` Wentao Guan
2025-09-20 4:16 ` [PATCH] " Huacai Chen
2025-09-20 8:25 ` [tip: core/core] " tip-bot2 for Yao Zi
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