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* [Bug tdep/28796] New: GDB locks up after stopping on a breakpoint in invalidated memory on aarch64
@ 2022-01-20 9:41 idan.horowitz at gmail dot com
2022-01-20 9:44 ` [Bug tdep/28796] " idan.horowitz at gmail dot com
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: idan.horowitz at gmail dot com @ 2022-01-20 9:41 UTC (permalink / raw)
To: gdb-prs
https://sourceware.org/bugzilla/show_bug.cgi?id=28796
Bug ID: 28796
Summary: GDB locks up after stopping on a breakpoint in
invalidated memory on aarch64
Product: gdb
Version: HEAD
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: tdep
Assignee: unassigned at sourceware dot org
Reporter: idan.horowitz at gmail dot com
Target Milestone: ---
When debugging a kernel inside QEMU aarch64-softmmu using GDB for
aarch64-none-linux-gnu, when GDB pauses execution after a breakpoint is hit in
invalidated memory (that is, memory that does not have a valid translation
yet), GDB locks up.
Meaning that execution can not be resumed again (using stepi/continue/advance
etc), this is due to the fact that GDB tries to read the memory at the current
PC when resuming execution, which it fails to do due to the invalid
translation, but this also stops it from stepping into the translation
exception handler, essentially locking up GDB completely.
I've tracked down said memory read to the following call:
https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=gdb/aarch64-tdep.c;h=63d626f90ace55f80c5d3e3d557993d905a90da1;hb=HEAD#l2869
This read is used to detect and execute load-exclusive/store-exclusive
sequences atomically, but the issue is the fact that this method uses the
unsafe read_memory_unsigned_integer method, which throws when a read fails,
instead of calling safe_read_memory_unsigned_integer and returning an empty
vector like the rest of the failure paths in this method do. This exception
then bubbles up to `resume_1` which cancels the resumption of the execution,
locking GDB in place.
--
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^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug tdep/28796] GDB locks up after stopping on a breakpoint in invalidated memory on aarch64 2022-01-20 9:41 [Bug tdep/28796] New: GDB locks up after stopping on a breakpoint in invalidated memory on aarch64 idan.horowitz at gmail dot com @ 2022-01-20 9:44 ` idan.horowitz at gmail dot com 2022-10-21 10:11 ` luis.machado at arm dot com ` (3 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: idan.horowitz at gmail dot com @ 2022-01-20 9:44 UTC (permalink / raw) To: gdb-prs https://sourceware.org/bugzilla/show_bug.cgi?id=28796 Idan Horowitz <idan.horowitz at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Target| |aarch64-none-linux-gnu -- You are receiving this mail because: You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tdep/28796] GDB locks up after stopping on a breakpoint in invalidated memory on aarch64 2022-01-20 9:41 [Bug tdep/28796] New: GDB locks up after stopping on a breakpoint in invalidated memory on aarch64 idan.horowitz at gmail dot com 2022-01-20 9:44 ` [Bug tdep/28796] " idan.horowitz at gmail dot com @ 2022-10-21 10:11 ` luis.machado at arm dot com 2022-10-21 10:11 ` luis.machado at arm dot com ` (2 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: luis.machado at arm dot com @ 2022-10-21 10:11 UTC (permalink / raw) To: gdb-prs https://sourceware.org/bugzilla/show_bug.cgi?id=28796 Luis Machado <luis.machado at arm dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |luis.machado at arm dot com Ever confirmed|0 |1 Status|UNCONFIRMED |ASSIGNED Last reconfirmed| |2022-10-21 --- Comment #1 from Luis Machado <luis.machado at arm dot com> --- Thanks for reporting this. Sorry for the late reply. I'll take a look at it. -- You are receiving this mail because: You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tdep/28796] GDB locks up after stopping on a breakpoint in invalidated memory on aarch64 2022-01-20 9:41 [Bug tdep/28796] New: GDB locks up after stopping on a breakpoint in invalidated memory on aarch64 idan.horowitz at gmail dot com 2022-01-20 9:44 ` [Bug tdep/28796] " idan.horowitz at gmail dot com 2022-10-21 10:11 ` luis.machado at arm dot com @ 2022-10-21 10:11 ` luis.machado at arm dot com 2022-11-10 0:45 ` cvs-commit at gcc dot gnu.org 2022-11-10 0:46 ` luis.machado at arm dot com 4 siblings, 0 replies; 6+ messages in thread From: luis.machado at arm dot com @ 2022-10-21 10:11 UTC (permalink / raw) To: gdb-prs https://sourceware.org/bugzilla/show_bug.cgi?id=28796 Luis Machado <luis.machado at arm dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Assignee|unassigned at sourceware dot org |luis.machado at arm dot com -- You are receiving this mail because: You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tdep/28796] GDB locks up after stopping on a breakpoint in invalidated memory on aarch64 2022-01-20 9:41 [Bug tdep/28796] New: GDB locks up after stopping on a breakpoint in invalidated memory on aarch64 idan.horowitz at gmail dot com ` (2 preceding siblings ...) 2022-10-21 10:11 ` luis.machado at arm dot com @ 2022-11-10 0:45 ` cvs-commit at gcc dot gnu.org 2022-11-10 0:46 ` luis.machado at arm dot com 4 siblings, 0 replies; 6+ messages in thread From: cvs-commit at gcc dot gnu.org @ 2022-11-10 0:45 UTC (permalink / raw) To: gdb-prs https://sourceware.org/bugzilla/show_bug.cgi?id=28796 --- Comment #2 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Luis Machado <luisgpm@sourceware.org>: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=94355de7751579b0182bd5821a3223939054f5d7 commit 94355de7751579b0182bd5821a3223939054f5d7 Author: Luis Machado <luis.machado@arm.com> Date: Mon Oct 31 13:26:20 2022 +0000 [gdb/aarch64] Use safer memory read routines PR tdep/28796 As reported, we are using some memory read routines that don't handle read errors gracefully. Convert those to use the safe_* versions if available. This allows the code to handle those read errors in a more sensible way. Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28796 -- You are receiving this mail because: You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tdep/28796] GDB locks up after stopping on a breakpoint in invalidated memory on aarch64 2022-01-20 9:41 [Bug tdep/28796] New: GDB locks up after stopping on a breakpoint in invalidated memory on aarch64 idan.horowitz at gmail dot com ` (3 preceding siblings ...) 2022-11-10 0:45 ` cvs-commit at gcc dot gnu.org @ 2022-11-10 0:46 ` luis.machado at arm dot com 4 siblings, 0 replies; 6+ messages in thread From: luis.machado at arm dot com @ 2022-11-10 0:46 UTC (permalink / raw) To: gdb-prs https://sourceware.org/bugzilla/show_bug.cgi?id=28796 Luis Machado <luis.machado at arm dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|ASSIGNED |RESOLVED Resolution|--- |FIXED --- Comment #3 from Luis Machado <luis.machado at arm dot com> --- Fixed. Please reopen if you see any issues. -- You are receiving this mail because: You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-11-10 0:46 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-01-20 9:41 [Bug tdep/28796] New: GDB locks up after stopping on a breakpoint in invalidated memory on aarch64 idan.horowitz at gmail dot com 2022-01-20 9:44 ` [Bug tdep/28796] " idan.horowitz at gmail dot com 2022-10-21 10:11 ` luis.machado at arm dot com 2022-10-21 10:11 ` luis.machado at arm dot com 2022-11-10 0:45 ` cvs-commit at gcc dot gnu.org 2022-11-10 0:46 ` luis.machado at arm dot com
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