linux-kernel - [PATCH 06/18] mm: make vm

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1461675385-5934-7-git-send-email-mhocko@kernel.org>
Date:	Tue, 26 Apr 2016 14:56:13 +0200
From:	Michal Hocko <mhocko@...nel.org>
To:	<linux-mm@...ck.org>, Andrew Morton <akpm@...ux-foundation.org>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Michal Hocko <mhocko@...e.com>,
	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
	Oleg Nesterov <oleg@...hat.com>,
	Andrea Arcangeli <aarcange@...hat.com>,
	Vlastimil Babka <vbabka@...e.cz>
Subject: [PATCH 06/18] mm: make vm_brk killable

From: Michal Hocko <mhocko@...e.com>

Now that all the callers handle vm_brk failure we can change it
wait for mmap_sem killable to help oom_reaper to not get blocked
just because vm_brk gets blocked behind mmap_sem readers.

Cc: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc: Oleg Nesterov <oleg@...hat.com>
Cc: Andrea Arcangeli <aarcange@...hat.com>
Acked-by: Vlastimil Babka <vbabka@...e.cz>
Signed-off-by: Michal Hocko <mhocko@...e.com>
---
 include/linux/mm.h | 2 +-
 mm/mmap.c          | 9 +++------
 2 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1085e025852a..7b52750caf9e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2003,7 +2003,7 @@ static inline void mm_populate(unsigned long addr, unsigned long len) {}
 #endif
 
 /* These take the mm semaphore themselves */
-extern unsigned long vm_brk(unsigned long, unsigned long);
+extern unsigned long __must_check vm_brk(unsigned long, unsigned long);
 extern int vm_munmap(unsigned long, size_t);
 extern unsigned long __must_check vm_mmap(struct file *, unsigned long,
         unsigned long, unsigned long,
diff --git a/mm/mmap.c b/mm/mmap.c
index 032605bda665..62cb02310494 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2712,12 +2712,9 @@ unsigned long vm_brk(unsigned long addr, unsigned long len)
 	unsigned long ret;
 	bool populate;
 
-	/*
-	 * XXX not all users are chcecking the return value, convert
-	 * to down_write_killable after they are able to cope with
-	 * error
-	 */
-	down_write(&mm->mmap_sem);
+	if (down_write_killable(&mm->mmap_sem))
+		return -EINTR;
+
 	ret = do_brk(addr, len);
 	populate = ((mm->def_flags & VM_LOCKED) != 0);
 	up_write(&mm->mmap_sem);
-- 
2.8.0.rc3