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Lance Richardson 78ac65e8e9 net: support compat 64-bit time in {s,g}etsockopt 
[ Upstream commit 988bf7243e ]

For the x32 ABI, struct timeval has two 64-bit fields. However
the kernel currently interprets the user-space values used for
the SO_RCVTIMEO and SO_SNDTIMEO socket options as having a pair
of 32-bit fields.

When the seconds portion of the requested timeout is less than 2**32,
the seconds portion of the effective timeout is correct but the
microseconds portion is zero.  When the seconds portion of the
requested timeout is zero and the microseconds portion is non-zero,
the kernel interprets the timeout as zero (never timeout).

Fix by using 64-bit time for SO_RCVTIMEO/SO_SNDTIMEO as required
for the ABI.

The code included below demonstrates the problem.

Results before patch:
    $ gcc -m64 -Wall -O2 -o socktmo socktmo.c && ./socktmo
    recv time: 2.008181 seconds
    send time: 2.015985 seconds

    $ gcc -m32 -Wall -O2 -o socktmo socktmo.c && ./socktmo
    recv time: 2.016763 seconds
    send time: 2.016062 seconds

    $ gcc -mx32 -Wall -O2 -o socktmo socktmo.c && ./socktmo
    recv time: 1.007239 seconds
    send time: 1.023890 seconds

Results after patch:
    $ gcc -m64 -O2 -Wall -o socktmo socktmo.c && ./socktmo
    recv time: 2.010062 seconds
    send time: 2.015836 seconds

    $ gcc -m32 -O2 -Wall -o socktmo socktmo.c && ./socktmo
    recv time: 2.013974 seconds
    send time: 2.015981 seconds

    $ gcc -mx32 -O2 -Wall -o socktmo socktmo.c && ./socktmo
    recv time: 2.030257 seconds
    send time: 2.013383 seconds

 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/socket.h>
 #include <sys/types.h>
 #include <sys/time.h>

 void checkrc(char *str, int rc)
 {
         if (rc >= 0)
                 return;

         perror(str);
         exit(1);
 }

 static char buf[1024];
 int main(int argc, char **argv)
 {
         int rc;
         int socks[2];
         struct timeval tv;
         struct timeval start, end, delta;

         rc = socketpair(AF_UNIX, SOCK_STREAM, 0, socks);
         checkrc("socketpair", rc);

         /* set timeout to 1.999999 seconds */
         tv.tv_sec = 1;
         tv.tv_usec = 999999;
         rc = setsockopt(socks[0], SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof tv);
         rc = setsockopt(socks[0], SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof tv);
         checkrc("setsockopt", rc);

         /* measure actual receive timeout */
         gettimeofday(&start, NULL);
         rc = recv(socks[0], buf, sizeof buf, 0);
         gettimeofday(&end, NULL);
         timersub(&end, &start, &delta);

         printf("recv time: %ld.%06ld seconds\n",
                (long)delta.tv_sec, (long)delta.tv_usec);

         /* fill send buffer */
         do {
                 rc = send(socks[0], buf, sizeof buf, 0);
         } while (rc > 0);

         /* measure actual send timeout */
         gettimeofday(&start, NULL);
         rc = send(socks[0], buf, sizeof buf, 0);
         gettimeofday(&end, NULL);
         timersub(&end, &start, &delta);

         printf("send time: %ld.%06ld seconds\n",
                (long)delta.tv_sec, (long)delta.tv_usec);
         exit(0);
 }

Fixes: 515c7af85e ("x32: Use compat shims for {g,s}etsockopt")
Reported-by: Gopal RajagopalSai <gopalsr83@gmail.com>
Signed-off-by: Lance Richardson <lance.richardson.net@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-19 10:20:24 +02:00
arch KVM: x86: remove APIC Timer periodic/oneshot spikes 2018-05-16 10:10:32 +02:00
block bfq-iosched: ensure to clear bic/bfqq pointers when preparing request 2018-05-01 12:58:19 -07:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto crypto: af_alg - fix possible uninit-value in alg_bind() 2018-05-16 10:10:23 +02:00
Documentation arm64: Add work around for Arm Cortex-A55 Erratum 1024718 2018-05-16 10:10:25 +02:00
drivers net/mlx5: E-Switch, Include VF RDMA stats in vport statistics 2018-05-19 10:20:24 +02:00
firmware License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs smb3: directory sync should not return an error 2018-05-16 10:10:30 +02:00
include mm, oom: fix concurrent munlock and oom reaper unmap, v3 2018-05-16 10:10:27 +02:00
init kmemcheck: stop using GFP_NOTRACK and SLAB_NOTRACK 2018-02-22 15:42:23 +01:00
ipc ipc/shm: fix use-after-free of shm file via remap_file_pages() 2018-04-24 09:36:23 +02:00
kernel perf/core: Fix possible Spectre-v1 indexing for ->aux_pages[] 2018-05-16 10:10:31 +02:00
lib errseq: Always report a writeback error once 2018-05-09 09:51:54 +02:00
mm mm, oom: fix concurrent munlock and oom reaper unmap, v3 2018-05-16 10:10:27 +02:00
net net: support compat 64-bit time in {s,g}etsockopt 2018-05-19 10:20:24 +02:00
samples samples/bpf: Partially fixes the bpf.o build 2018-04-26 11:02:12 +02:00
scripts kconfig: Fix expr_free() E_NOT leak 2018-04-26 11:02:08 +02:00
security commoncap: Handle memory allocation failure. 2018-04-29 11:33:16 +02:00
sound ALSA: aloop: Add missing cable lock to ctl API callbacks 2018-05-09 09:51:50 +02:00
tools test_firmware: fix setting old custom fw path back on exit, second try 2018-05-09 09:51:54 +02:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt arm/arm64: KVM: Add PSCI version selection API 2018-05-01 12:58:27 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: rpm-pkg: keep spec file until make mrproper 2018-02-13 10:19:46 +01:00
.mailmap .mailmap: Add Maciej W. Rozycki's Imagination e-mail address 2017-11-10 12:16:15 -08:00
COPYING
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS dt-bindings: Document mti,mips-cpc binding 2018-03-15 10:54:35 +01:00
Makefile Linux 4.14.41 2018-05-16 10:10:32 +02:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README 

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.