On Sat, 25 Jul 2026 23:51:56 +0900, Takashi Yano via Cygwin wrote:
Hi Christian, Thanks for the report. On Sat, 25 Jul 2026 15:12:54 +0200 Christian Franke wrote:After 524d75ff ("Cygwin: open: Unlock fdtab before open_with_arch()"), CI workflow shows that 'stress-ng --procfs ...' now hangs. Testcase: $ uname -r # not with 3.7.0-0.567.g161e3cb999fb.x86_64 3.7.0-0.569.g524d75ff7398.x86_64 $ cat proc-self-fd.c #include <errno.h> #include <fcntl.h> #include <pthread.h> #include <stdio.h> #include <unistd.h> static void * threadfunc(void * arg) { (void)arg; for (int i = 0; i < 100000; i++) { char path[32]; snprintf(path, sizeof(path), "/proc/self/fd/%d", i % 10); int fd = open(path, O_RDONLY); if (fd < 0) { printf("%p#%06d: %s: errno=%d\n", pthread_self(), i, path, errno); continue; } printf("%p#%06d: %s: fd=%d\n", pthread_self(), i, path, fd); close(fd); } return NULL; } int main() { pthread_t t = NULL; int ret = pthread_create(&t, NULL, threadfunc, NULL); if (ret) return 1; threadfunc(NULL); ret = pthread_join(t, NULL); printf("pthread_join(%p, .)=%d\n", t, ret); if (ret) return 1; return 0; } $ gcc -o proc-self-fd proc-self-fd.c $ ./proc-self-fd ... 0xa00000500#001908: /proc/self/fd/8: errno=2 0xa00000010#001900: /proc/self/fd/0: fd=3 0xa00000500#001909: /proc/self/fd/9: errno=2 0xa00000010#001901: /proc/self/fd/1: errno=14<== EFAULT [hangs, kill -9 does not work] $ strace -o trace.log ./proc-self-fd [taskkill /f /im proc-self-fd.exe in other window] $ less trace.log ... 25 21725 [main] proc-self-fd 14876 fhandler_pty_slave::open_setup: /dev/pty1 opened, usecount 3 61 21786 [main] proc-self-fd 14876 build_fh_pc: found an archetype for (null)(136/1) io_handle 0x200 66 21852 [main] proc-self-fd 14876 build_fh_pc: fh 0x800008E40, dev 00880001 71 21923 [main] proc-self-fd 14876 fhandler_base::open_with_arch: line 471: /dev/pty1<0x8000086F0> usecount + 1 = 4 --- Process 3968 (pid: 14876), exception c0000008 at 00007ff81682416a --- Process 3968 (pid: 14876), exception c0000008 at 00007ff81682416a ... "... found an archetype for (null) ..." <== Hmm...Perhaps, this is due to the defects pointed out by Johannes. https://cygwin.com/pipermail/cygwin-patches/2026q3/015227.html
These are possibly fixed now. With 3.7.0-0.579.g61b4866baf41, the above testcase completes as expected.
-- Regards, Christian -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation: https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
