Re: [PATCH v2 4/6] powerpc/kdump: preserve user-specified memory limit

Hari Bathini
2025-01-23T10:30:34Z

On 21/01/25 5:24 pm, Sourabh Jain wrote:
> Commit 59d58189f3d9 ("crash: fix crash memory reserve exceed system
> memory bug") fails crashkernel parsing if the crash size is found to be
> higher than system RAM, which makes the memory_limit adjustment code
> ineffective due to an early exit from reserve_crashkernel().
>
> Regardless lets not violated the user-specified memory limit by

s/violated/violate/

> adjusting it. Remove this adjustment to ensure all reservations stay
> within the limit. Commit f94f5ac07983 ("powerpc/fadump: Don't update
> the user-specified memory limit") did the same for fadump.
>

Acked-by: Hari Bathini <hbathini@linux.ibm.com>

> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Baoquan he <bhe@redhat.com>
> Cc: Hari Bathini <hbathini@linux.ibm.com>
> CC: Madhavan Srinivasan <maddy@linux.ibm.com>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: kexec@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> Reviewed-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
> Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
> ---
> arch/powerpc/kexec/core.c | 8 --------
> 1 file changed, 8 deletions(-)
>
> diff --git a/arch/powerpc/kexec/core.c b/arch/powerpc/kexec/core.c
> index b8333a49ea5d..4945b33322ae 100644
> --- a/arch/powerpc/kexec/core.c
> +++ b/arch/powerpc/kexec/core.c
> @@ -150,14 +150,6 @@ void __init reserve_crashkernel(void)
> return;
> }
>
> - /* Crash kernel trumps memory limit */
> - if (memory_limit && memory_limit <= crashk_res.end) {
> - memory_limit = crashk_res.end + 1;
> - total_mem_sz = memory_limit;
> - printk("Adjusted memory limit for crashkernel, now 0x%llx\n",
> - memory_limit);
> - }
> -
> printk(KERN_INFO "Reserving %ldMB of memory at %ldMB "
> "for crashkernel (System RAM: %ldMB)\n",
> (unsigned long)(crash_size >> 20),