Re: [PATCH dovetail 6.x] x86: dovetail: Fix inband IRQ state corruption on out-of-band compat syscall

[Philippe Gerum <rpm@xenomai.org>]

Florian Bezdeka <florian.bezdeka@siemens.com> writes:

> The following kernel splat was found when running the Xenomai 3
> testsuite in compat on dovetail enabled kernels:
>
> [  513.620975] IRQ pipeline: some code running in oob context 'Xenomai'
>                              called an in-band only routine
> [  513.620998] CPU: 0 PID: 510 Comm: smokey Not tainted 6.10.0+ #76
> [  513.621003] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
> [  513.621005] IRQ stage: Xenomai
> [  513.621007] Call Trace:
> [  513.621011]  <TASK>
> [  513.621015]  dump_stack_lvl+0x6f/0xd0
> [  513.621202]  __inband_irq_enable+0xb/0x60
> [  513.621249]  do_int80_emulation+0x68/0x160
> [  513.621265]  asm_int80_emulation+0x1a/0x20
> [  513.621285] RIP: 0023:0xf7f692ba
> [  513.621288] Code: Unable to access opcode bytes at 0xf7f69290.
> [  513.621303] RSP: 002b:00000000ffeedf40 EFLAGS: 00000282 ORIG_RAX: 0000000000000127
> [  513.621307] RAX: ffffffffffffffda RBX: 00000000ffffff9c RCX: 00000000ffeedfa0
> [  513.621309] RDX: 0000000000088000 RSI: 0000000000000000 RDI: 00000000f7f7aff4
> [  513.621311] RBP: 00000000ffeedf88 R08: 0000000000000000 R09: 0000000000000000
> [  513.621313] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> [  513.621315] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> [  513.621319]  </TASK>
>
> When entering the low level entry code from the out-of-band stage
> the in-band IRQ state was changed. That is now avoided by calling
> syscall_enter_from_user_enable_irqs() as all other entry points do.
>
> Signed-off-by: Florian Bezdeka <florian.bezdeka@siemens.com>
> ---
>  arch/x86/entry/common.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
> index 467e2511df2e..13589f1ca89b 100644
> --- a/arch/x86/entry/common.c
> +++ b/arch/x86/entry/common.c
> @@ -259,7 +259,7 @@ __visible noinstr void do_int80_emulation(struct pt_regs *regs)
>  
>  	nr = syscall_32_enter(regs);
>  
> -	local_irq_enable_full();
> +	syscall_enter_from_user_enable_irqs();
>  	nr = syscall_enter_from_user_mode_work(regs, nr);
>  
>  	if (dovetailing()) {

Ack. Merged into 6.1.y, 6.6.y and 6.11, dovetail and evl trees.

-- 
Philippe.