Re: [PATCH] mm, memory-failure: clarify error message

From: Verma, Vishal L
Date: Fri May 17 2019 - 14:22:56 EST


On Thu, 2019-05-16 at 22:08 -0600, Jane Chu wrote:
> Some user who install SIGBUS handler that does longjmp out
> therefore keeping the process alive is confused by the error
> message
> "[188988.765862] Memory failure: 0x1840200: Killing
> cellsrv:33395 due to hardware memory corruption"
> Slightly modify the error message to improve clarity.
>
> Signed-off-by: Jane Chu <jane.chu@xxxxxxxxxx>
> ---
> mm/memory-failure.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index fc8b517..14de5e2 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -216,10 +216,9 @@ static int kill_proc(struct to_kill *tk, unsigned long pfn, int flags)
> short addr_lsb = tk->size_shift;
> int ret;
>
> - pr_err("Memory failure: %#lx: Killing %s:%d due to hardware memory corruption\n",
> - pfn, t->comm, t->pid);
> -
> if ((flags & MF_ACTION_REQUIRED) && t->mm == current->mm) {
> + pr_err("Memory failure: %#lx: Killing %s:%d due to hardware memory "
> + "corruption\n", pfn, t->comm, t->pid);

Minor nit, but the string shouldn't be split over multiple lines to
preserve grep-ability. In such a case it is usually considered OK to
exceed 80 characters for the line if needed.

> ret = force_sig_mceerr(BUS_MCEERR_AR, (void __user *)tk->addr,
> addr_lsb, current);
> } else {
> @@ -229,6 +228,8 @@ static int kill_proc(struct to_kill *tk, unsigned long pfn, int flags)
> * This could cause a loop when the user sets SIGBUS
> * to SIG_IGN, but hopefully no one will do that?
> */
> + pr_err("Memory failure: %#lx: Sending SIGBUS to %s:%d due to hardware "
> + "memory corruption\n", pfn, t->comm, t->pid);
> ret = send_sig_mceerr(BUS_MCEERR_AO, (void __user *)tk->addr,
> addr_lsb, t); /* synchronous? */
> }