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Filename Latest commit message Latest commit date
Tetsuo Handa 09c4506525 tipc: fix shutdown() of connectionless socket
[ Upstream commit 2a63866c8b51a3f72cea388dfac259d0e14c4ba6 ]

syzbot is reporting hung task at nbd_ioctl() [1], for there are two
problems regarding TIPC's connectionless socket's shutdown() operation.

----------
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <linux/nbd.h>
#include <unistd.h>

int main(int argc, char *argv[])
{
        const int fd = open("/dev/nbd0", 3);
        alarm(5);
        ioctl(fd, NBD_SET_SOCK, socket(PF_TIPC, SOCK_DGRAM, 0));
        ioctl(fd, NBD_DO_IT, 0); /* To be interrupted by SIGALRM. */
        return 0;
}
----------

One problem is that wait_for_completion() from flush_workqueue() from
nbd_start_device_ioctl() from nbd_ioctl() cannot be completed when
nbd_start_device_ioctl() received a signal at wait_event_interruptible(),
for tipc_shutdown() from kernel_sock_shutdown(SHUT_RDWR) from
nbd_mark_nsock_dead() from sock_shutdown() from nbd_start_device_ioctl()
is failing to wake up a WQ thread sleeping at wait_woken() from
tipc_wait_for_rcvmsg() from sock_recvmsg() from sock_xmit() from
nbd_read_stat() from recv_work() scheduled by nbd_start_device() from
nbd_start_device_ioctl(). Fix this problem by always invoking
sk->sk_state_change() (like inet_shutdown() does) when tipc_shutdown() is
called.

The other problem is that tipc_wait_for_rcvmsg() cannot return when
tipc_shutdown() is called, for tipc_shutdown() sets sk->sk_shutdown to
SEND_SHUTDOWN (despite "how" is SHUT_RDWR) while tipc_wait_for_rcvmsg()
needs sk->sk_shutdown set to RCV_SHUTDOWN or SHUTDOWN_MASK. Fix this
problem by setting sk->sk_shutdown to SHUTDOWN_MASK (like inet_shutdown()
does) when the socket is connectionless.

[1] https://syzkaller.appspot.com/bug?id=3fe51d307c1f0a845485cf1798aa059d12bf18b2

Reported-by: syzbot <syzbot+e36f41d207137b5d12f7@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-12 14:18:55 +02:00
arch arm64: dts: mt7622: add reset node for mmc device 2020-09-09 19:12:33 +02:00
block blk-iocost: ioc_pd_free() shouldn't assume irq disabled 2020-09-09 19:12:35 +02:00
certs
crypto crypto: af_alg - Work around empty control messages without MSG_MORE 2020-09-03 11:27:05 +02:00
Documentation affs: fix basic permission bits to actually work 2020-09-09 19:12:34 +02:00
drivers net: usb: dm9601: Add USB ID of Keenetic Plus DSL 2020-09-12 14:18:55 +02:00
fs affs: fix basic permission bits to actually work 2020-09-09 19:12:34 +02:00
include libata: implement ATA_HORKAGE_MAX_TRIM_128M and apply to Sandisks 2020-09-09 19:12:34 +02:00
init
ipc
kernel kbuild: add variables for compression tools 2020-09-03 11:27:10 +02:00
lib
LICENSES
mm mm/khugepaged.c: fix khugepaged's request size in collapse_file 2020-09-09 19:12:37 +02:00
net tipc: fix shutdown() of connectionless socket 2020-09-12 14:18:55 +02:00
samples
scripts checkpatch: fix the usage of capture group ( ... ) 2020-09-09 19:12:37 +02:00
security
sound ALSA: hda/realtek - Improved routing for Thinkpad X1 7th/8th Gen 2020-09-09 19:12:33 +02:00
tools perf record: Correct the help info of option "--no-bpf-event" 2020-09-09 19:12:36 +02:00
usr
virt KVM: arm64: Only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is not set 2020-08-26 10:41:08 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
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Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.64 2020-09-09 19:12:37 +02:00
README

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

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.