Re: [PATCH] fs: use kvmalloc for big coredump file

[Zhaoyang Huang]

loop Eric W

On Tue, Aug 30, 2022 at 2:56 PM zhaoyang.huang
<zhaoyang.huang@xxxxxxxxxx> wrote:
>
> From: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx>
>
> High order page allocation observed which even introduce kernel panic when generating
> coredump file, use kvmalloc_array instead of kmalloc_array
>
> [68058.982108] init: Untracked pid 3847 exited with status 0
> [68058.982343] init: Untracked pid 3847 did not have an associated service entry and will not be reaped
> [68059.038127] warn_alloc: 29 callbacks suppressed
> [68059.038132] TimerThread: page allocation failure: order:7, mode:0x40dc0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO), nodemask=(null),cpuset=foreground,mems_allowed=0
> [68059.038155] CPU: 6 PID: 3597 Comm: TimerThread Tainted: G        W  OE     5.15.41-android13-8-01198-g03458ee9a090-ab000039 #1
> [68059.038159] Hardware name: Unisoc UMS9620-base Board (DT)
> [68059.038161] Call trace:
> [68059.038163]  dump_backtrace.cfi_jt+0x0/0x8
> [68059.038169]  dump_stack_lvl+0x98/0xe8
> [68059.038174]  warn_alloc+0x164/0x200
> [68059.038180]  __alloc_pages_slowpath+0x9d4/0xb64
> [68059.038183]  __alloc_pages+0x21c/0x39c
> [68059.038186]  kmalloc_order+0x4c/0x13c
> [68059.038189]  kmalloc_order_trace+0x34/0x154
> [68059.038192]  __kmalloc+0x600/0x8a8
> [68059.038196]  elf_core_dump+0x7c4/0x15d8
> [68059.038201]  do_coredump+0x680/0xe54
> [68059.038203]  get_signal+0x610/0x988
> [68059.038209]  do_signal+0xd4/0x2bc
> [68059.038213]  do_notify_resume+0xa0/0x1c8
> [68059.038216]  el0_svc+0x68/0x90
> [68059.038219]  el0t_64_sync_handler+0x88/0xec
> [68059.038222]  el0t_64_sync+0x1b4/0x1b8
>
> Reported-by: Guanglu Xu <guanglu.xu@xxxxxxxxxx>
> Signed-off-by: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx>
> ---
>  fs/coredump.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/coredump.c b/fs/coredump.c
> index ebc43f9..ed9b191 100644
> --- a/fs/coredump.c
> +++ b/fs/coredump.c
> @@ -213,7 +213,7 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm,
>
>         if (ispipe) {
>                 int argvs = sizeof(core_pattern) / 2;
> -               (*argv) = kmalloc_array(argvs, sizeof(**argv), GFP_KERNEL);
> +               (*argv) = kvmalloc_array(argvs, sizeof(**argv), GFP_KERNEL);
>                 if (!(*argv))
>                         return -ENOMEM;
>                 (*argv)[(*argc)++] = 0;
> @@ -612,7 +612,7 @@ void do_coredump(const kernel_siginfo_t *siginfo)
>                         goto fail_dropcount;
>                 }
>
> -               helper_argv = kmalloc_array(argc + 1, sizeof(*helper_argv),
> +               helper_argv = kvmalloc_array(argc + 1, sizeof(*helper_argv),
>                                             GFP_KERNEL);
>                 if (!helper_argv) {
>                         printk(KERN_WARNING "%s failed to allocate memory\n",
> --
> 1.9.1
>