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author | Takashi Yano <takashi.yano@nifty.ne.jp> | 2022-01-13 20:57:15 +0900 |
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committer | Takashi Yano <takashi.yano@nifty.ne.jp> | 2022-01-14 23:11:07 +0900 |
commit | bff4594b089c10c41edcdd14c2682d19f36b3241 (patch) | |
tree | f0735eeaf87a177558122c2275f8f43d9aae6807 | |
parent | 3af461092e7ee9b76f3a1c18a6d95ed6e226df81 (diff) | |
download | newlib-bff4594b089c10c41edcdd14c2682d19f36b3241.zip newlib-bff4594b089c10c41edcdd14c2682d19f36b3241.tar.gz newlib-bff4594b089c10c41edcdd14c2682d19f36b3241.tar.bz2 |
Cygwin: console: Fix potential deadlock regarding acuqiring mutex.
- Acquiring input_mutex and attach_mutex in console code has potential
risk of deadlock. This patch fixes the issue.
-rw-r--r-- | winsup/cygwin/fhandler.h | 2 | ||||
-rw-r--r-- | winsup/cygwin/select.cc | 7 |
2 files changed, 6 insertions, 3 deletions
diff --git a/winsup/cygwin/fhandler.h b/winsup/cygwin/fhandler.h index 0cea1b7..fb47476 100644 --- a/winsup/cygwin/fhandler.h +++ b/winsup/cygwin/fhandler.h @@ -2208,9 +2208,11 @@ private: void acquire_input_mutex_if_necessary (DWORD ms) { acquire_input_mutex (ms); + acquire_attach_mutex (ms); } void release_input_mutex_if_necessary (void) { + release_attach_mutex (); release_input_mutex (); } diff --git a/winsup/cygwin/select.cc b/winsup/cygwin/select.cc index 5b8fc0f..d01a319 100644 --- a/winsup/cygwin/select.cc +++ b/winsup/cygwin/select.cc @@ -1122,29 +1122,30 @@ peek_console (select_record *me, bool) HANDLE h; set_handle_or_return_if_not_open (h, me); + fh->acquire_input_mutex (mutex_timeout); acquire_attach_mutex (mutex_timeout); while (!fh->input_ready && !fh->get_cons_readahead_valid ()) { if (fh->bg_check (SIGTTIN, true) <= bg_eof) { release_attach_mutex (); + fh->release_input_mutex (); return me->read_ready = true; } else if (!PeekConsoleInputW (h, &irec, 1, &events_read) || !events_read) break; - fh->acquire_input_mutex (mutex_timeout); if (fhandler_console::input_winch == fh->process_input_message () && global_sigs[SIGWINCH].sa_handler != SIG_IGN && global_sigs[SIGWINCH].sa_handler != SIG_DFL) { set_sig_errno (EINTR); - fh->release_input_mutex (); release_attach_mutex (); + fh->release_input_mutex (); return -1; } - fh->release_input_mutex (); } release_attach_mutex (); + fh->release_input_mutex (); if (fh->input_ready || fh->get_cons_readahead_valid ()) return me->read_ready = true; |