Re: [PATCH v2] sparc64: increase kernel thread stack size to 32K

[Stian Halseth]

Hi Imre,

Sending V3 with two separate patches now.

Thank for the feedback and testing!

Stian

On Sun, 2026-09-27 at 22:49 +0200, Imre Kaloz wrote:
> Hi Stian,
> 
> I ran this on a Sun Ultra 45 (UltraSPARC IIIi, SMP). The unpatched
> kernel hits "corrupted stack end detected inside scheduler" in
> hub_power_on() on 10 out of 10 boots with USB devices attached. With
> the 32K stack it boots clean every time: 6 boots with the v1 diff,
> 10 more with the minimal diff below. A forced hub/device rebind with
> the stack tracer armed peaked at 15832 of 32768 bytes, so 32K looks
> like plenty here.
> 
> On v1, Andreas agreed with 32K but asked for the dead else branches
> to be pulled into their own patch with a fixup tag for 15b9350a177b,
> since that commit should have removed them already. v2 folds the
> removal into the same patch, so I'd split it back out for v3: the
> fix as the minimal diff below, the else-branch removal as its own
> patch on top. Nice work!
> 
> The minimal diff is below the scissors, feel free to fold it in.
> 
> Tested-by: Imre Kaloz <kaloz@xxxxxxxxxx> # Sun Ultra 45
> 
> 
> Best,
> Imre
> 
> -- >8 --
> Signed-off-by: Imre Kaloz <kaloz@xxxxxxxxxx>
> ---
> diff --git a/arch/sparc/include/asm/thread_info_64.h
> b/arch/sparc/include/asm/thread_info_64.h
> index c8a73dff27f8..ec552513d63c 100644
> --- a/arch/sparc/include/asm/thread_info_64.h
> +++ b/arch/sparc/include/asm/thread_info_64.h
> @@ -100,8 +100,8 @@ struct thread_info {
>  #define	FAULT_CODE_BAD_RA	0x20	/* Bad RA for
> sun4v		   */
>  
>  #if PAGE_SHIFT == 13
> -#define THREAD_SIZE (2*PAGE_SIZE)
> -#define THREAD_SHIFT (PAGE_SHIFT + 1)
> +#define THREAD_SIZE (4*PAGE_SIZE)
> +#define THREAD_SHIFT (PAGE_SHIFT + 2)
>  #else /* PAGE_SHIFT == 13 */
>  #define THREAD_SIZE PAGE_SIZE
>  #define THREAD_SHIFT PAGE_SHIFT
> @@ -129,7 +129,7 @@ extern struct thread_info
> *current_thread_info(void);
>  
>  /* thread information allocation */
>  #if PAGE_SHIFT == 13
> -#define THREAD_SIZE_ORDER	1
> +#define THREAD_SIZE_ORDER	2
>  #else /* PAGE_SHIFT == 13 */
>  #define THREAD_SIZE_ORDER	0
>  #endif /* PAGE_SHIFT == 13 */

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