From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, TSUKADA Koutaro <tsukada@ascade.co.jp>,
Oleg Nesterov <oleg@redhat.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH 4.9 01/21] kernel/acct.c: fix the acct->needcheck check in check_free_space()
Date: Mon, 8 Jan 2018 13:59:21 +0100 [thread overview]
Message-ID: <20180108125920.176340344@linuxfoundation.org> (raw)
In-Reply-To: <20180108125920.106264989@linuxfoundation.org>
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Oleg Nesterov <oleg@redhat.com>
commit 4d9570158b6260f449e317a5f9ed030c2504a615 upstream.
As Tsukada explains, the time_is_before_jiffies(acct->needcheck) check
is very wrong, we need time_is_after_jiffies() to make sys_acct() work.
Ignoring the overflows, the code should "goto out" if needcheck >
jiffies, while currently it checks "needcheck < jiffies" and thus in the
likely case check_free_space() does nothing until jiffies overflow.
In particular this means that sys_acct() is simply broken, acct_on()
sets acct->needcheck = jiffies and expects that check_free_space()
should set acct->active = 1 after the free-space check, but this won't
happen if jiffies increments in between.
This was broken by commit 32dc73086015 ("get rid of timer in
kern/acct.c") in 2011, then another (correct) commit 795a2f22a8ea
("acct() should honour the limits from the very beginning") made the
problem more visible.
Link: http://lkml.kernel.org/r/20171213133940.GA6554@redhat.com
Fixes: 32dc73086015 ("get rid of timer in kern/acct.c")
Reported-by: TSUKADA Koutaro <tsukada@ascade.co.jp>
Suggested-by: TSUKADA Koutaro <tsukada@ascade.co.jp>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/acct.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -99,7 +99,7 @@ static int check_free_space(struct bsd_a
{
struct kstatfs sbuf;
- if (time_is_before_jiffies(acct->needcheck))
+ if (time_is_after_jiffies(acct->needcheck))
goto out;
/* May block */
next prev parent reply other threads:[~2018-01-08 13:02 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-08 12:59 [PATCH 4.9 00/21] 4.9.76-stable review Greg Kroah-Hartman
2018-01-08 12:59 ` Greg Kroah-Hartman [this message]
2018-01-08 12:59 ` [PATCH 4.9 02/21] crypto: n2 - cure use after free Greg Kroah-Hartman
2018-01-08 12:59 ` [PATCH 4.9 03/21] crypto: chacha20poly1305 - validate the digest size Greg Kroah-Hartman
2018-01-08 12:59 ` [PATCH 4.9 04/21] crypto: pcrypt - fix freeing pcrypt instances Greg Kroah-Hartman
2018-01-08 12:59 ` [PATCH 4.9 06/21] fscache: Fix the default for fscache_maybe_release_page() Greg Kroah-Hartman
2018-01-08 12:59 ` [PATCH 4.9 07/21] nbd: fix use-after-free of rq/bio in the xmit path Greg Kroah-Hartman
2018-01-08 12:59 ` [PATCH 4.9 08/21] kernel: make groups_sort calling a responsibility group_info allocators Greg Kroah-Hartman
2018-01-08 12:59 ` [PATCH 4.9 09/21] kernel/signal.c: protect the traced SIGNAL_UNKILLABLE tasks from SIGKILL Greg Kroah-Hartman
2018-01-08 12:59 ` [PATCH 4.9 10/21] kernel/signal.c: protect the SIGNAL_UNKILLABLE tasks from !sig_kernel_only() signals Greg Kroah-Hartman
2018-01-08 12:59 ` [PATCH 4.9 11/21] kernel/signal.c: remove the no longer needed SIGNAL_UNKILLABLE check in complete_signal() Greg Kroah-Hartman
2018-01-08 12:59 ` [PATCH 4.9 12/21] iommu/arm-smmu-v3: Dont free page table ops twice Greg Kroah-Hartman
2018-01-08 12:59 ` [PATCH 4.9 13/21] iommu/arm-smmu-v3: Cope with duplicated Stream IDs Greg Kroah-Hartman
2018-01-08 12:59 ` [PATCH 4.9 14/21] ARC: uaccess: dont use "l" gcc inline asm constraint modifier Greg Kroah-Hartman
2018-01-08 12:59 ` [PATCH 4.9 15/21] Input: elantech - add new icbody type 15 Greg Kroah-Hartman
2018-01-08 12:59 ` [PATCH 4.9 16/21] x86/microcode/AMD: Add support for fam17h microcode loading Greg Kroah-Hartman
2018-01-08 12:59 ` [PATCH 4.9 17/21] parisc: Fix alignment of pa_tlb_lock in assembly on 32-bit SMP kernel Greg Kroah-Hartman
2018-01-08 12:59 ` [PATCH 4.9 18/21] parisc: qemu idle sleep support Greg Kroah-Hartman
2018-01-08 12:59 ` [PATCH 4.9 20/21] x86/tlb: Drop the _GPL from the cpu_tlbstate export Greg Kroah-Hartman
2018-01-08 12:59 ` [PATCH 4.9 21/21] Map the vsyscall page with _PAGE_USER Greg Kroah-Hartman
2018-01-08 20:59 ` [PATCH 4.9 00/21] 4.9.76-stable review Shuah Khan
2018-01-09 11:59 ` Naresh Kamboju
2018-01-09 12:42 ` Greg Kroah-Hartman
2018-01-09 13:45 ` Guenter Roeck
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