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From: "simark at simark dot ca" <sourceware-bugzilla@sourceware.org>
To: gdb-prs@sourceware.org
Subject: [Bug gdb/28412] syscall that writes memory does not trigger hardware watchpoint.
Date: Sat, 09 Oct 2021 17:26:38 +0000 [thread overview]
Message-ID: <bug-28412-4717-rHLNS9XBqQ@http.sourceware.org/bugzilla/> (raw)
In-Reply-To: <bug-28412-4717@http.sourceware.org/bugzilla/>
https://sourceware.org/bugzilla/show_bug.cgi?id=28412
Simon Marchi <simark at simark dot ca> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |simark at simark dot ca
--- Comment #1 from Simon Marchi <simark at simark dot ca> ---
(In reply to Yichao Yu from comment #0)
> When a watchpoint is set on `c` with `watch -l c` or `watch c`, the value is
> changed by `read` without triggering the watch point. Turning off hardware
> watchpoint fixes the issue. Seems that when hardware watch point is used,
> checks needs to be added around syscalls to see if they modify memory?
That sounds doable (although at a cost). GDB uses PTRACE_SYSCALL to cause the
program to stop on syscall entry only if the user has set up some syscall
catchpoints. But it could also be enabled if the user has some hardware
watchpoints set. When a thread exits, we would get an event, and we could
check all watchpoints, see if the memory they watch has changed.
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next prev parent reply other threads:[~2021-10-09 17:26 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-02 19:16 [Bug gdb/28412] New: " yyc1992 at gmail dot com
2021-10-09 11:25 ` [Bug gdb/28412] " ssbssa at sourceware dot org
2021-10-09 17:26 ` simark at simark dot ca [this message]
2022-03-06 17:15 ` tromey at sourceware dot org
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