From: Omar Sandoval <osandov@osandov.com>
To: Al Viro <viro@zeniv.linux.org.uk>,
Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-team@fb.com, Omar Sandoval <osandov@fb.com>
Subject: [PATCH RESEND v3 2/2] coredump: only charge written data against RLIMIT_CORE
Date: Wed, 11 May 2016 15:16:37 -0700 [thread overview]
Message-ID: <36e748cf9ab3181f6e325850cab7aabb758dd026.1463004510.git.osandov@fb.com> (raw)
In-Reply-To: <cover.1463004510.git.osandov@fb.com>
In-Reply-To: <cover.1463004510.git.osandov@fb.com>
From: Omar Sandoval <osandov@fb.com>
Commit 9b56d54380ad ("dump_skip(): dump_seek() replacement taking
coredump_params") introduced a regression with regard to RLIMIT_CORE.
Previously, when a core dump was sparse, only the data that was actually
written out would count against the limit. Now, the sparse ranges are
also included, which leads to truncated core dumps when the actual disk
usage is still well below the limit. Restore the old behavior by only
counting what gets emitted and ignoring what gets skipped.
Signed-off-by: Omar Sandoval <osandov@fb.com>
---
fs/coredump.c | 5 ++---
include/linux/binfmts.h | 1 +
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/coredump.c b/fs/coredump.c
index 9db0c514438e..492c2db25dc9 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -782,7 +782,7 @@ int dump_emit(struct coredump_params *cprm, const void *addr, int nr)
struct file *file = cprm->file;
loff_t pos = file->f_pos;
ssize_t n;
- if (pos + nr > cprm->limit)
+ if (cprm->written + nr > cprm->limit)
return 0;
while (nr) {
if (dump_interrupted())
@@ -791,6 +791,7 @@ int dump_emit(struct coredump_params *cprm, const void *addr, int nr)
if (n <= 0)
return 0;
file->f_pos = pos;
+ cprm->written += n;
nr -= n;
}
return 1;
@@ -802,8 +803,6 @@ int dump_skip(struct coredump_params *cprm, size_t nr)
static char zeroes[PAGE_SIZE];
struct file *file = cprm->file;
if (file->f_op->llseek && file->f_op->llseek != no_llseek) {
- if (file->f_pos + nr > cprm->limit)
- return 0;
if (dump_interrupted() ||
file->f_op->llseek(file, nr, SEEK_CUR) < 0)
return 0;
diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index 39c6d6e1234e..576e4639ca60 100644
--- a/include/linux/binfmts.h
+++ b/include/linux/binfmts.h
@@ -64,6 +64,7 @@ struct coredump_params {
struct file *file;
unsigned long limit;
unsigned long mm_flags;
+ loff_t written;
};
/*
--
2.8.2
next prev parent reply other threads:[~2016-05-11 22:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-11 22:16 [PATCH RESEND v3 0/2] fix RLIMIT_CORE accounting for sparse dumps Omar Sandoval
2016-05-11 22:16 ` [PATCH RESEND v3 1/2] coredump: get rid of coredump_params->written Omar Sandoval
2016-05-11 22:16 ` Omar Sandoval [this message]
2016-05-11 22:18 ` [PATCH RESEND v3 0/2] fix RLIMIT_CORE accounting for sparse dumps Al Viro
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