From: Greg KH <gregkh@suse.de>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org,
alan@lxorguk.ukuu.org.uk, "J. Bruce Fields" <bfields@redhat.com>
Subject: [16/27] svcrpc: fix double-free on shutdown of nfsd after changing pool mode
Date: Mon, 23 Jan 2012 15:41:02 -0800 [thread overview]
Message-ID: <20120123234203.025513019@clark.kroah.org> (raw)
In-Reply-To: <20120123234224.GA19510@kroah.com>
2.6.32-longterm review patch. If anyone has any objections, please let me know.
------------------
From: "J. Bruce Fields" <bfields@redhat.com>
commit 61c8504c428edcebf23b97775a129c5b393a302b upstream.
The pool_to and to_pool fields of the global svc_pool_map are freed on
shutdown, but are initialized in nfsd startup only in the
SVC_POOL_PERCPU and SVC_POOL_PERNODE cases.
They *are* initialized to zero on kernel startup. So as long as you use
only SVC_POOL_GLOBAL (the default), this will never be a problem.
You're also OK if you only ever use SVC_POOL_PERCPU or SVC_POOL_PERNODE.
However, the following sequence events leads to a double-free:
1. set SVC_POOL_PERCPU or SVC_POOL_PERNODE
2. start nfsd: both fields are initialized.
3. shutdown nfsd: both fields are freed.
4. set SVC_POOL_GLOBAL
5. start nfsd: the fields are left untouched.
6. shutdown nfsd: now we try to free them again.
Step 4 is actually unnecessary, since (for some bizarre reason), nfsd
automatically resets the pool mode to SVC_POOL_GLOBAL on shutdown.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
net/sunrpc/svc.c | 3 +++
1 file changed, 3 insertions(+)
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -166,6 +166,7 @@ svc_pool_map_alloc_arrays(struct svc_poo
fail_free:
kfree(m->to_pool);
+ m->to_pool = NULL;
fail:
return -ENOMEM;
}
@@ -286,7 +287,9 @@ svc_pool_map_put(void)
if (!--m->count) {
m->mode = SVC_POOL_DEFAULT;
kfree(m->to_pool);
+ m->to_pool = NULL;
kfree(m->pool_to);
+ m->pool_to = NULL;
m->npools = 0;
}
next prev parent reply other threads:[~2012-01-23 23:45 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-23 23:42 [00/27] 2.6.32.55-longterm review Greg KH
2012-01-23 23:40 ` [01/27] ext4: fix undefined behavior in ext4_fill_flex_info() Greg KH
2012-01-23 23:40 ` [02/27] ALSA: snd-usb-us122l: Delete calls to preempt_disable Greg KH
2012-01-23 23:40 ` [03/27] ALSA: ice1724 - Check for ac97 to avoid kernel oops Greg KH
2012-01-23 23:40 ` [04/27] ALSA: hda - Return the error from get_wcaps_type() for invalid NIDs Greg KH
2012-01-23 23:40 ` [05/27] HID: bump maximum global item tag report size to 96 bytes Greg KH
2012-01-23 23:40 ` [06/27] UBI: fix use-after-free on error path Greg KH
2012-01-23 23:40 ` [07/27] PCI: Fix PCI_EXP_TYPE_RC_EC value Greg KH
2012-01-23 23:40 ` [08/27] PCI: msi: Disable msi interrupts when we initialize a pci device Greg KH
2012-01-23 23:40 ` [09/27] xen/xenbus: Reject replies with payload > XENSTORE_PAYLOAD_MAX Greg KH
2012-01-23 23:40 ` [10/27] ima: free duplicate measurement memory Greg KH
2012-01-23 23:40 ` [11/27] PNP: work around Dell 1536/1546 BIOS MMCONFIG bug that breaks USB Greg KH
2012-01-23 23:40 ` [12/27] x86: Fix mmap random address range Greg KH
2012-01-23 23:40 ` [13/27] UBI: fix nameless volumes handling Greg KH
2012-01-23 23:41 ` [14/27] i2c: Fix error value returned by several bus drivers Greg KH
2012-01-23 23:41 ` [15/27] [media] V4L/DVB: v4l2-ioctl: integer overflow in video_usercopy() Greg KH
2012-01-23 23:41 ` Greg KH [this message]
2012-01-23 23:41 ` [17/27] svcrpc: destroy server sockets all at once Greg KH
2012-01-23 23:41 ` [18/27] nfsd: Fix oops when parsing a 0 length export Greg KH
2012-01-23 23:41 ` [19/27] USB: cdc-wdm: fix misuse of logical operation in place of bitop Greg KH
2012-01-23 23:41 ` [20/27] [S390] fix cputime overflow in uptime_proc_show Greg KH
2012-01-23 23:41 ` [21/27] USB: Fix bad dma problem on WDM device disconnect Greg KH
2012-01-23 23:41 ` [22/27] block: add and use scsi_blk_cmd_ioctl Greg KH
2012-01-23 23:41 ` [23/27] kernel.h: add printk_ratelimited and pr_<level>_rl Greg KH
2012-01-24 14:46 ` Phil Carmody
2012-01-24 16:35 ` Ben Hutchings
2012-01-24 16:43 ` Greg KH
2012-01-23 23:41 ` [24/27] ALSA: HDA: Fix internal microphone on Dell Studio 16 XPS 1645 Greg KH
2012-01-23 23:41 ` [25/27] [SCSI] sym53c8xx: Fix NULL pointer dereference in slave_destroy Greg KH
2012-01-23 23:41 ` [26/27] score: fix off-by-one index into syscall table Greg KH
2012-01-23 23:41 ` [27/27] kprobes: initialize before using a hlist Greg KH
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