Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1313680

[PATCH 4.1 37/43] af_unix: Revert lock_interruptible in stream receive code

Show all headers | View raw

4.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Rainer Weikusat <rweikusat@mobileactivedefense.com>

[ Upstream commit 3822b5c2fc62e3de8a0f33806ff279fb7df92432 ]

With b3ca9b02b00704053a38bfe4c31dbbb9c13595d0, the AF_UNIX SOCK_STREAM
receive code was changed from using mutex_lock(&u->readlock) to
mutex_lock_interruptible(&u->readlock) to prevent signals from being
delayed for an indefinite time if a thread sleeping on the mutex
happened to be selected for handling the signal. But this was never a
problem with the stream receive code (as opposed to its datagram
counterpart) as that never went to sleep waiting for new messages with the
mutex held and thus, wouldn't cause secondary readers to block on the
mutex waiting for the sleeping primary reader. As the interruptible
locking makes the code more complicated in exchange for no benefit,
change it back to using mutex_lock.

Signed-off-by: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/unix/af_unix.c |   13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2072,14 +2072,7 @@ static int unix_stream_recvmsg(struct so
 
 	memset(&scm, 0, sizeof(scm));
 
-	err = mutex_lock_interruptible(&u->readlock);
-	if (unlikely(err)) {
-		/* recvmsg() in non blocking mode is supposed to return -EAGAIN
-		 * sk_rcvtimeo is not honored by mutex_lock_interruptible()
-		 */
-		err = noblock ? -EAGAIN : -ERESTARTSYS;
-		goto out;
-	}
+	mutex_lock(&u->readlock);
 
 	if (flags & MSG_PEEK)
 		skip = sk_peek_offset(sk, flags);
@@ -2120,12 +2113,12 @@ again:
 
 			timeo = unix_stream_data_wait(sk, timeo, last);
 
-			if (signal_pending(current)
-			    ||  mutex_lock_interruptible(&u->readlock)) {
+			if (signal_pending(current)) {
 				err = sock_intr_errno(timeo);
 				goto out;
 			}
 
+			mutex_lock(&u->readlock);
 			continue;
  unlock:
 			unix_state_unlock(sk);

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH 4.1 00/43] 4.1.16-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-21 00:20 +0100
  [PATCH 4.1 40/43] KEYS: Fix race between key destruction and finding a keyring by name Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-21 00:20 +0100
  [PATCH 4.1 25/43] sh_eth: fix kernel oops in skb_put() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-21 00:20 +0100
  [PATCH 4.1 39/43] rhashtable: Fix walker list corruption Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-21 00:20 +0100
  [PATCH 4.1 31/43] net_sched: make qdisc_tree_decrease_qlen() work for non mq Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-21 00:20 +0100
  [PATCH 4.1 37/43] af_unix: Revert lock_interruptible in stream receive code Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-21 00:20 +0100
  [PATCH 4.1 20/43] sctp: also copy sk_tsflags when copying the socket Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-21 00:20 +0100
  [PATCH 4.1 11/43] usb: core : hub: Fix BOS NULL pointer kernel panic Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-21 00:30 +0100
  [PATCH 4.1 05/43] usb-storage: Fix scsi-sd failure "Invalid field in cdb" for USB adapter JMicron Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-21 00:30 +0100
  [PATCH 4.1 15/43] atl1c: Improve driver not to do order 4 GFP_ATOMIC allocation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-21 00:30 +0100
  [PATCH 4.1 10/43] usb: musb: USB_TI_CPPI41_DMA requires dmaengine support Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-21 00:30 +0100
  [PATCH 4.1 04/43] USB: serial: Another Infineon flash loader USB ID Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-21 00:30 +0100
  [PATCH 4.1 01/43] tpm, tpm_tis: fix tpm_tis ACPI detection issue with TPM 2.0 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-21 00:30 +0100
  [PATCH 4.1 07/43] USB: add quirk for devices with broken LPM Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-21 00:30 +0100
  [PATCH 4.1 12/43] usb: Use the USB_SS_MULT() macro to decode burst multiplier for log message Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-21 00:30 +0100
  [PATCH 4.1 13/43] pppoe: fix memory corruption in padt work structure Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-21 00:30 +0100
  [PATCH 4.1 06/43] USB: cp210x: Remove CP2110 ID from compatibility list Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-21 00:30 +0100
  [PATCH 4.1 17/43] vxlan: fix incorrect RCO bit in VXLAN header Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-21 00:30 +0100
  [PATCH 4.1 14/43] gre6: allow to update all parameters via rtnl Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-21 00:30 +0100
  [PATCH 4.1 03/43] USB: cdc_acm: Ignore Infineon Flash Loader utility Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-21 00:30 +0100
  Re: [PATCH 4.1 00/43] 4.1.16-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2016-01-21 01:00 +0100
  Re: [PATCH 4.1 00/43] 4.1.16-stable review Guenter Roeck <linux@roeck-us.net> - 2016-01-21 13:30 +0100

csiph-web