From 60d1eeac6c6185ac77b181929c773015a2772fe8 Mon Sep 17 00:00:00 2001 From: Corinna Vinschen Date: Mon, 30 Oct 2023 19:40:31 +0100 Subject: [PATCH] Cygwin: cwd: avoid releasing the cwdstuff SRW Lock twice cwdstuff::set has a code snippet handling the case where a process can't create a handle to a directory, e. g., due to permissions. Commit 88443b0a22589 ("cwdstuff: Don't leave from setting the CWD prematurely on init") introduced a special case to handle this situation at process initialization. It also introduces an early mutex release, which is not required, but ok, because we're in the init phase. Releasing the mutex twice is no problem since the mutexes are recursive. Fast forward to commit 0819679a7a210 ("Cygwin: cwd: use SRWLOCK instead of muto"). The mechanical change from a recursive mutex to a non-recursive SRWLOCK failed to notice that this very specific situation will release the SRWLOCK twice. Remove the superfluous release action. While at it, don't set dir to NULL, but h, since dir will get the value of h anyway later on. Setting h to NULL may not be necessary, but better safe than sorry. Reported-by: tryandbuy >tryandbuy@proton.me> Fixes: 88443b0a22589 ("cwdstuff: Don't leave from setting the CWD prematurely on init") Fixes: 0819679a7a210 ("Cygwin: cwd: use SRWLOCK instead of muto") Signed-off-by: Corinna Vinschen --- winsup/cygwin/path.cc | 3 +-- winsup/cygwin/release/3.4.10 | 3 +++ 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/winsup/cygwin/path.cc b/winsup/cygwin/path.cc index 1c3583d76..c3f84f7f8 100644 --- a/winsup/cygwin/path.cc +++ b/winsup/cygwin/path.cc @@ -4868,10 +4868,9 @@ cwdstuff::set (path_conv *nat_cwd, const char *posix_cwd) peb.ProcessParameters->CurrentDirectoryHandle, GetCurrentProcess (), &h, 0, TRUE, 0)) { - release_write (); if (peb.ProcessParameters->CurrentDirectoryHandle) debug_printf ("...and DuplicateHandle failed with %E."); - dir = NULL; + h = NULL; } } } diff --git a/winsup/cygwin/release/3.4.10 b/winsup/cygwin/release/3.4.10 index f34b131b3..c75283991 100644 --- a/winsup/cygwin/release/3.4.10 +++ b/winsup/cygwin/release/3.4.10 @@ -3,3 +3,6 @@ Bug Fixes - Fix missing term in __cpuset_zero_s() prototoype in sys/cpuset.h. Addresses: https://cygwin.com/pipermail/cygwin/2023-September/254423.html + +- Fix hang in process initialization if cwd is unreadable. + Addresses: https://cygwin.com/pipermail/cygwin/2023-October/254604.html