On Mon, Mar 04, 2024 at 07:43:39PM +0100, Mikulas Patocka wrote:
> Hi
>
> I have a program that sets up a periodic timer with 10ms interval. When
> the program attempts to call fallocate on tmpfs, it goes into an infinite
> loop. fallocate takes longer than 10ms, so it gets interrupted by a
> signal and it returns EINTR. On EINTR, the fallocate call is restarted,
> going into the same loop again.
>
> fallocate(19, FALLOC_FL_KEEP_SIZE, 0, 206057565) = -1 EINTR (Přerušené volání systému)
> --- SIGALRM {si_signo=SIGALRM, si_code=SI_TIMER, si_timerid=0, si_overrun=0, si_int=0, si_ptr=NULL} ---
> sigreturn({mask=[]}) = -1 EINTR (Přerušené volání systému)
> fallocate(19, FALLOC_FL_KEEP_SIZE, 0, 206057565) = -1 EINTR (Přerušené volání systému)
> --- SIGALRM {si_signo=SIGALRM, si_code=SI_TIMER, si_timerid=0, si_overrun=0, si_int=0, si_ptr=NULL} ---
> sigreturn({mask=[]}) = -1 EINTR (Přerušené volání systému)
> fallocate(19, FALLOC_FL_KEEP_SIZE, 0, 206057565) = -1 EINTR (Přerušené volání systému)
> --- SIGALRM {si_signo=SIGALRM, si_code=SI_TIMER, si_timerid=0, si_overrun=0, si_int=0, si_ptr=NULL} ---
> sigreturn({mask=[]}) = -1 EINTR (Přerušené volání systému)
> fallocate(19, FALLOC_FL_KEEP_SIZE, 0, 206057565) = -1 EINTR (Přerušené volání systému)
> --- SIGALRM {si_signo=SIGALRM, si_code=SI_TIMER, si_timerid=0, si_overrun=0, si_int=0, si_ptr=NULL} ---
> sigreturn({mask=[]}) = -1 EINTR (Přerušené volání systému)
>
> Should there be fatal_signal_pending instead of signal_pending in the
> shmem_fallocate loop?
>
> Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
>
> ---
> mm/shmem.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> Index: linux-2.6/mm/shmem.c
> ===================================================================
> --- linux-2.6.orig/mm/shmem.c 2024-01-18 19:18:31.000000000 +0100
> +++ linux-2.6/mm/shmem.c 2024-03-04 19:05:25.000000000 +0100
> @@ -3143,7 +3143,7 @@ static long shmem_fallocate(struct file
> * Good, the fallocate(2) manpage permits EINTR: we may have
> * been interrupted because we are using up too much memory.
> */
> - if (signal_pending(current))
> + if (fatal_signal_pending(current))
I think that's likely wrong and probably would cause regressions as
there may be users relying on this?
