[PATCH] coredump: add cond_resched() to dump_user_range

[PATCH] coredump: add cond_resched() to dump_user_range

[Rik van Riel]

The loop between elf_core_dump() and dump_user_range() can run for
so long that the system shows softlockup messages, with side effects
like workqueues and RCU getting stuck on the core dumping CPU.

Add a cond_resched() in dump_user_range() to avoid that softlockup.

Signed-off-by: Rik van Riel <riel@surriel.com>
---
 fs/coredump.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/coredump.c b/fs/coredump.c
index 53a78b6bbb5b..14c385ffbcc9 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -1020,6 +1020,7 @@ int dump_user_range(struct coredump_params *cprm, unsigned long start,
 		} else {
 			dump_skip(cprm, PAGE_SIZE);
 		}
+		cond_resched();
 	}
 	dump_page_free(dump_page);
 	return 1;
-- 
2.45.2

Re: [PATCH] coredump: add cond_resched() to dump_user_range

[Christian Brauner]

On Thu, 10 Oct 2024 11:36:51 -0400, Rik van Riel wrote:
> The loop between elf_core_dump() and dump_user_range() can run for
> so long that the system shows softlockup messages, with side effects
> like workqueues and RCU getting stuck on the core dumping CPU.
> 
> Add a cond_resched() in dump_user_range() to avoid that softlockup.
> 
> 
> [...]

Applied to the vfs.misc branch of the vfs/vfs.git tree.
Patches in the vfs.misc branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs.misc

[1/1] coredump: add cond_resched() to dump_user_range
      https://git.kernel.org/vfs/vfs/c/89be051f0724