Re: [PATCH] coredump: Limit what can interrupt coredumps

[Olivier Langlois <olivier@trillion01.com>]

On Tue, 2021-08-17 at 12:24 -0600, Jens Axboe wrote:
> 
> And assuming that works, then I suspect this one would fix your issue
> even with a piped core dump:
> 
> diff --git a/fs/coredump.c b/fs/coredump.c
> index 07afb5ddb1c4..852737a9ccbf 100644
> --- a/fs/coredump.c
> +++ b/fs/coredump.c
> @@ -41,6 +41,7 @@
>  #include <linux/fs.h>
>  #include <linux/path.h>
>  #include <linux/timekeeping.h>
> +#include <linux/io_uring.h>
>  
>  #include <linux/uaccess.h>
>  #include <asm/mmu_context.h>
> @@ -603,6 +604,7 @@ void do_coredump(const kernel_siginfo_t *siginfo)
>         };
>  
>         audit_core_dumps(siginfo->si_signo);
> +       io_uring_task_cancel();
>  
>         binfmt = mm->binfmt;
>         if (!binfmt || !binfmt->core_dump)
> 
That is what my patch is doing. Function call is inserted at a
different place... I am not sure if one location is better than the
other or if it matters at all but there is an extra change required to
make it work...

diff --git a/fs/coredump.c b/fs/coredump.c
index 07afb5ddb1c4..614fe7a54c1a 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -41,6 +41,7 @@
 #include <linux/fs.h>
 #include <linux/path.h>
 #include <linux/timekeeping.h>
+#include <linux/io_uring.h>
 
 #include <linux/uaccess.h>
 #include <asm/mmu_context.h>
@@ -625,6 +626,8 @@ void do_coredump(const kernel_siginfo_t *siginfo)
 		need_suid_safe = true;
 	}
 
+	io_uring_task_cancel();
+
 	retval = coredump_wait(siginfo->si_signo, &core_state);
 	if (retval < 0)
 		goto fail_creds;