Skip to content

K
kernel_linux

OpenHarmony / kernel_linux
上一次同步 大约 4 年

通知 14
Star 8
Fork 2
K
kernel_linux
切换分支/标签
  1. 16 7月, 2012 2 次提交
    • A
      fifo: Do not restart open() if it already found a partner · 05d290d6
      由 Anders Kaseorg 提交于 
      If a parent and child process open the two ends of a fifo, and the
child immediately exits, the parent may receive a SIGCHLD before its
open() returns.  In that case, we need to make sure that open() will
return successfully after the SIGCHLD handler returns, instead of
throwing EINTR or being restarted.  Otherwise, the restarted open()
would incorrectly wait for a second partner on the other end.

The following test demonstrates the EINTR that was wrongly thrown from
the parent’s open().  Change .sa_flags = 0 to .sa_flags = SA_RESTART
to see a deadlock instead, in which the restarted open() waits for a
second reader that will never come.  (On my systems, this happens
pretty reliably within about 5 to 500 iterations.  Others report that
it manages to loop ~forever sometimes; YMMV.)

  #include <sys/stat.h>
  #include <sys/types.h>
  #include <sys/wait.h>
  #include <fcntl.h>
  #include <signal.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <unistd.h>

  #define CHECK(x) do if ((x) == -1) {perror(#x); abort();} while(0)

  void handler(int signum) {}

  int main()
  {
      struct sigaction act = {.sa_handler = handler, .sa_flags = 0};
      CHECK(sigaction(SIGCHLD, &act, NULL));
      CHECK(mknod("fifo", S_IFIFO | S_IRWXU, 0));
      for (;;) {
          int fd;
          pid_t pid;
          putc('.', stderr);
          CHECK(pid = fork());
          if (pid == 0) {
              CHECK(fd = open("fifo", O_RDONLY));
              _exit(0);
          }
          CHECK(fd = open("fifo", O_WRONLY));
          CHECK(close(fd));
          CHECK(waitpid(pid, NULL, 0));
      }
  }

This is what I suspect was causing the Git test suite to fail in
t9010-svn-fe.sh:

	http://bugs.debian.org/678852Signed-off-by: NAnders Kaseorg <andersk@mit.edu>
Reviewed-by: NJonathan Nieder <jrnieder@gmail.com>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      05d290d6
    • L
      Merge tag 'fixes-for-v3.5-rc6' of... · 1694a0a0
      由 Linus Torvalds 提交于 
      Merge tag 'fixes-for-v3.5-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl

Pull late pinctrl fixes from Linus Walleij:
- Two fixes to the i.MX driver

* tag 'fixes-for-v3.5-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl:
  pinctrl: pinctrl-imx6q: add missed mux function for USBOTG_ID
  pinctrl: pinctrl-imx: only print debug message when DEBUG is defined
      1694a0a0
  3. 15 7月, 2012 10 次提交
  5. 14 7月, 2012 14 次提交
  7. 13 7月, 2012 10 次提交
  9. 12 7月, 2012 4 次提交