diff mbox series

[137/156] coredump: let dump_emit() bail out on short writes

Message ID 20201016024938.1zaQbvIF0%akpm@linux-foundation.org (mailing list archive)
State New
Headers show
Series [001/156] device-dax/kmem: fix resource release | expand

Commit Message

Andrew Morton Oct. 16, 2020, 2:49 a.m. UTC
From: Jann Horn <jannh@google.com>
Subject: coredump: let dump_emit() bail out on short writes

dump_emit() has a retry loop, but there seems to be no way for that retry
logic to actually be used; and it was also buggy, writing the same data
repeatedly after a short write.

Let's just bail out on a short write.

Link: http://lkml.kernel.org/r/20200827114932.3572699-3-jannh@google.com
Signed-off-by: Jann Horn <jannh@google.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/coredump.c |   22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)
diff mbox series

Patch

--- a/fs/coredump.c~coredump-let-dump_emit-bail-out-on-short-writes
+++ a/fs/coredump.c
@@ -840,17 +840,17 @@  int dump_emit(struct coredump_params *cp
 	ssize_t n;
 	if (cprm->written + nr > cprm->limit)
 		return 0;
-	while (nr) {
-		if (dump_interrupted())
-			return 0;
-		n = __kernel_write(file, addr, nr, &pos);
-		if (n <= 0)
-			return 0;
-		file->f_pos = pos;
-		cprm->written += n;
-		cprm->pos += n;
-		nr -= n;
-	}
+
+
+	if (dump_interrupted())
+		return 0;
+	n = __kernel_write(file, addr, nr, &pos);
+	if (n != nr)
+		return 0;
+	file->f_pos = pos;
+	cprm->written += n;
+	cprm->pos += n;
+
 	return 1;
 }
 EXPORT_SYMBOL(dump_emit);