[Crash-utility] Re: [PATCH] get vmalloc start address from vmcoreinfo
On 01/03/24 12:32 pm, Aditya Gupta wrote:
Below error is noticed when running crash on vmcore collected from a
linux-next
kernel crash (linux-next tag next-20240121):
# crash /boot/vmlinuz-6.8.0-rc5-next-20240221 ./vmcore
……
……
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crash: page excluded: kernel virtual address: c00000000219a2c0 type: “vmlist"
This occured since getting the vmalloc area base address doesn't work in
crash now, due to 'vmap_area_list' being removed in the linux kernel with
below commit (in linux-next tree):
commit 378eb24a0658dd922b29524e0ce35c6c43f56cba
mm/vmalloc: remove vmap_area_list
As an alternative, the commit introduced 'VMALLOC_START' in vmcoreinfo to
get base address of vmalloc area, use it to return vmallow start address
instead of depending on vmap_area_list and vmlist
LGTM.
Acked-by: Hari Bathini <hbathini(a)linux.ibm.com>
> Reported-by: Sachin Sant <sachinp(a)linux.ibm.com>
> Signed-off-by: Aditya Gupta <adityag(a)linux.ibm.com>
> ---
> memory.c | 11 ++++++++++-
> 1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/memory.c b/memory.c
> index b84e974a3325..b3027bd101cd 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -17220,11 +17220,20 @@ first_vmalloc_address(void)
> {
> static ulong vmalloc_start = 0;
> ulong vm_struct, vmap_area;
> + char *vmalloc_start_string;
>
> if (DUMPFILE() && vmalloc_start)
> return vmalloc_start;
>
> - if (vt->flags & USE_VMAP_AREA) {
> + /*
> + * 'vmap_area_list' and 'vmlist' in newer kernels might be empty,
prefer
> + * `VMALLOC_START` if exported in vmcoreinfo
> + */
> + vmalloc_start_string = pc->read_vmcoreinfo("NUMBER(VMALLOC_START)");
> + if (vmalloc_start_string) {
> + vmalloc_start = stol(vmalloc_start_string, QUIET, NULL);
> + free(vmalloc_start_string);
> + } else if (vt->flags & USE_VMAP_AREA) {
> get_symbol_data("vmap_area_list", sizeof(void *), &vmap_area);
> if (!vmap_area)
> return 0;