Re: [PATCH] mm/vmalloc: add alignment info in warning print as possible failure reason

Re: [PATCH] mm/vmalloc: add alignment info in warning print as possible failure reason

[Uladzislau Rezki]

On Thu, Jul 02, 2026 at 07:26:10PM +0800, Feng Tang wrote:
> When running 'fix_align_alloc_test' case of test_vmalloc module with
> command:
>     insmod ./test_vmalloc.ko run_test_mask=64
> 
> It will fail, which is the expected result, as the case increment
> the alignment parameter gradually to 64bit limit. And the dmesg has
> warning msg:
>     "vmalloc_test/0: vmalloc error: size 4096, vm_struct allocation failed, mode:0xdc0(GFP_KERNEL|__GFP_ZERO), nodemask=(null),cpuset=/,mems_allowed=0"
> 
> It doesn't give the alignment info, which is the real reason for the
> failure (not the 'size').
> 
> Add alignment info to the warning print to give the necessary hint
> for possible failure reason, and the message will be:
>     "vmalloc_test/0: vmalloc error: size 4096, align 0x800000000000, vm_struct allocation failed, mode:0xdc0(GFP_KERNEL|__GFP_ZERO), nodemask=(null),cpuset=/,mems_allowed=0"
> 
> Signed-off-by: Feng Tang <feng.tang@linux.alibaba.com>
> ---
>  mm/vmalloc.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 1afca3568b9b..e066324dcc76 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -4045,8 +4045,8 @@ void *__vmalloc_node_range_noprof(unsigned long size, unsigned long align,
>  	if (!area) {
>  		bool nofail = gfp_mask & __GFP_NOFAIL;
>  		warn_alloc(gfp_mask, NULL,
> -			"vmalloc error: size %lu, vm_struct allocation failed%s",
> -			size, (nofail) ? ". Retrying." : "");
> +			"vmalloc error: size %lu, align 0x%lx, vm_struct allocation failed%s",
> +			size, align, (nofail) ? ". Retrying." : "");
>  		if (nofail) {
>  			schedule_timeout_uninterruptible(1);
>  			goto again;
> -- 
> 2.43.5
> 
Do not see any issues with adding extra information on failure.

Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>

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Uladzislau Rezki