Re: [PATCH v5] crash: Fix crash memory reserve exceed system memory bug

Baoquan He
2024-07-23T05:17:59Z

On 07/23/24 at 10:07am, Jinjie Ruan wrote:
> On x86_32 Qemu machine with 1GB memory, the cmdline "crashkernel=4G" is ok
> as below:
> crashkernel reserved: 0x0000000020000000 - 0x0000000120000000 (4096 MB)
>
> It's similar on other architectures, such as ARM32 and RISCV32.
>
> The cause is that the crash_size is parsed and printed with "unsigned long
> long" data type which is 8 bytes but allocated used with "phys_addr_t"
> which is 4 bytes in memblock_phys_alloc_range().
>
> Fix it by checking if crash_size is greater than system RAM size and
> return error if so.
>
> After this patch, there is no above confusing reserve success info.
>
> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
> Suggested-by: Baoquan He <bhe@redhat.com>
> Suggested-by: Mike Rapoport <rppt@kernel.org>

My Suggested-by can be taken off because I suggested to check the parsed
value after parse_crashkernel(), Mike's suggestion is better.

For this version,

Acked-by: Baoquan He <bhe@redhat.com>

> ---
> v5:
> - Fix it in common parse_crashkernel() instead of per-arch.
> - Add suggested-by.
>
> v4:
> - Update the warn info to align with parse_crashkernel_mem().
> - Rebased on the "ARM: Use generic interface to simplify crashkernel
> reservation" patch.
> - Also fix for riscv32.
> - Update the commit message.
>
> v3:
> - Handle the check in reserve_crashkernel() Baoquan suggested.
> - Split x86_32 and arm32.
> - Add Suggested-by.
> - Drop the wrong fix tag.
>
> v2:
> - Also fix for x86_32.
> - Update the fix method.
> - Peel off the other two patches.
> - Update the commit message.
> ---
> kernel/crash_reserve.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/kernel/crash_reserve.c b/kernel/crash_reserve.c
> index ad5b3f2c5487..5387269114f6 100644
> --- a/kernel/crash_reserve.c
> +++ b/kernel/crash_reserve.c
> @@ -335,6 +335,9 @@ int __init parse_crashkernel(char *cmdline,
> if (!*crash_size)
> ret = -EINVAL;
>
> + if (*crash_size >= system_ram)
> + ret = -EINVAL;
> +
> return ret;
> }
>
> --
> 2.34.1
>