public inbox for cygwin-cvs@sourceware.org help / color / mirror / Atom feed
From: Takashi Yano <tyan0@sourceware.org> To: cygwin-cvs@sourceware.org Subject: [newlib-cygwin] Cygwin: console: Fix potential deadlock regarding acuqiring mutex. Date: Fri, 14 Jan 2022 14:15:03 +0000 (GMT) [thread overview] Message-ID: <20220114141503.D4EB73835C07@sourceware.org> (raw) https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=bff4594b089c10c41edcdd14c2682d19f36b3241 commit bff4594b089c10c41edcdd14c2682d19f36b3241 Author: Takashi Yano <takashi.yano@nifty.ne.jp> Date: Thu Jan 13 20:57:15 2022 +0900 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. Diff: --- winsup/cygwin/fhandler.h | 2 ++ 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 0cea1b7f3..fb4747608 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 5b8fc0f81..d01a319ef 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;
reply other threads:[~2022-01-14 14:15 UTC|newest] Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20220114141503.D4EB73835C07@sourceware.org \ --to=tyan0@sourceware.org \ --cc=cygwin-cvs@sourceware.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).