From: John Baldwin <jhb@FreeBSD.org>
To: Tom Tromey <tom@tromey.com>, gdb-patches@sourceware.org
Subject: Re: [RFC 5/6] Introduce thread-safe way to handle SIGSEGV
Date: Mon, 11 Mar 2019 17:24:00 -0000 [thread overview]
Message-ID: <b4d33933-1830-2a83-0c6f-58ba38581d91@FreeBSD.org> (raw)
In-Reply-To: <20190309172300.2764-6-tom@tromey.com>
On 3/9/19 9:22 AM, Tom Tromey wrote:
> The gdb demangler installs a SIGSEGV handler in order to protect gdb
> from demangler bugs. However, this is not thread-safe, as signal
> handlers are global to the process.
>
> This patch changes gdb to always install a global SIGSEGV handler, and
> then lets thread indicate their interest in handling the signal by
> setting a thread-local variable.
>
> This patch then arranges for the demangler code to use this; being
> sure to arrange for calls to warning and the like to be done on the
> main thread.
The one downside of always having a handler is that the $_siginfo after
a "normal" sig11 in GDB won't be valid anymore (it will have SI_USER
set now instead and si_addr won't be valid, etc.). We could "fix" this
by having signal frames supply $_siginfo though I'm not sure what
the most intuitive model of that would be.
--
John Baldwin
next prev parent reply other threads:[~2019-03-11 17:24 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-09 17:23 [RFC 0/6] Demangle minimal symbol names in worker threads Tom Tromey
2019-03-09 17:23 ` [RFC 3/6] Lock the demangled hash table Tom Tromey
2019-03-09 17:23 ` [RFC 6/6] Demangle minsyms in parallel Tom Tromey
2019-03-09 17:23 ` [RFC 5/6] Introduce thread-safe way to handle SIGSEGV Tom Tromey
2019-03-11 17:24 ` John Baldwin [this message]
2019-03-09 17:23 ` [RFC 2/6] Remove static buffer from ada_decode Tom Tromey
2019-03-09 17:23 ` [RFC 4/6] Introduce run_on_main_thread Tom Tromey
2019-03-09 17:23 ` [RFC 1/6] Defer minimal symbol name-setting Tom Tromey
2019-03-09 18:09 ` [RFC 0/6] Demangle minimal symbol names in worker threads Eli Zaretskii
2019-03-11 17:35 ` John Baldwin
2019-03-11 22:39 ` Tom Tromey
2019-03-12 3:33 ` Eli Zaretskii
2019-03-13 15:38 ` Eli Zaretskii
2019-03-15 23:28 ` Tom Tromey
2019-03-16 7:46 ` Eli Zaretskii
2019-03-16 8:31 ` Eli Zaretskii
2019-03-15 23:40 ` Tom Tromey
2019-03-16 7:52 ` Eli Zaretskii
2019-03-11 17:26 ` John Baldwin
2019-03-11 22:40 ` Tom Tromey
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