From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jann Horn Date: Wed, 29 Apr 2020 21:49:51 +0000 Subject: [PATCH v2 2/5] coredump: Let dump_emit() bail out on short writes Message-Id: <20200429214954.44866-3-jannh@google.com> List-Id: References: <20200429214954.44866-1-jannh@google.com> In-Reply-To: <20200429214954.44866-1-jannh@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Andrew Morton Cc: Rich Felker , linux-c6x-dev@linux-c6x.org, Yoshinori Sato , linux-sh@vger.kernel.org, linux-kernel@vger.kernel.org, Oleg Nesterov , linux-mm@kvack.org, Alexander Viro , Mark Salter , linux-fsdevel@vger.kernel.org, Russell King , Aurelien Jacquiot , Linus Torvalds , Christoph Hellwig , linux-arm-kernel@lists.infradead.org, "Eric W . Biederman" 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. Suggested-by: Linus Torvalds Signed-off-by: Jann Horn --- fs/coredump.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/fs/coredump.c b/fs/coredump.c index 408418e6aa131..d6fcc36a7db1f 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -823,17 +823,17 @@ int dump_emit(struct coredump_params *cprm, const void *addr, int nr) 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); -- 2.26.2.526.g744177e7f7-goog