* [ob/pushed] gdbserver: Fix incorrect assertion
@ 2022-03-21 16:48 Pedro Alves
2022-03-21 17:04 ` [pushed] gdbserver: Fixup previous patch Pedro Alves
0 siblings, 1 reply; 2+ messages in thread
From: Pedro Alves @ 2022-03-21 16:48 UTC (permalink / raw)
To: gdb-patches
While playing with adding a new event kind, I noticed that
prepare_resume_reply TARGET_WAITKIND_FORKED, etc. advance 'buf', so if
we force-disable the T packet, we'd fail the *buf == 'T' assertion.
Fix it by tweaking the assertion to always look at the beginning of
the buffer.
Change-Id: I8c38e32353db115edcde418b3b1e8ba12343c22b
---
gdbserver/remote-utils.cc | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/gdbserver/remote-utils.cc b/gdbserver/remote-utils.cc
index 3004130fb25..0599cc9c4f1 100644
--- a/gdbserver/remote-utils.cc
+++ b/gdbserver/remote-utils.cc
@@ -1070,6 +1070,7 @@ prepare_resume_reply (char *buf, ptid_t ptid, const target_waitstatus &status)
{
const char **regp;
struct regcache *regcache;
+ char *buf_start = buf;
if ((status.kind () == TARGET_WAITKIND_FORKED && cs.report_fork_events)
|| (status.kind () == TARGET_WAITKIND_VFORKED
@@ -1140,11 +1141,11 @@ prepare_resume_reply (char *buf, ptid_t ptid, const target_waitstatus &status)
An 'S' stop packet always looks like 'Sxx', so all we do
here is convert the buffer from a T packet to an S packet
and the avoid adding any extra content by breaking out. */
- gdb_assert (*buf == 'T');
- gdb_assert (isxdigit (*(buf + 1)));
- gdb_assert (isxdigit (*(buf + 2)));
+ gdb_assert (buf_start[0] == 'T');
+ gdb_assert (isxdigit (buf_start[1]));
+ gdb_assert (isxdigit (buf_start[2]));
*buf = 'S';
- *(buf + 3) = '\0';
+ buf_start[3] = '\0';
break;
}
base-commit: f55649cc9bcb92405d49af6bdcde6e69ac4d1c49
--
2.26.2
^ permalink raw reply [flat|nested] 2+ messages in thread
* [pushed] gdbserver: Fixup previous patch
2022-03-21 16:48 [ob/pushed] gdbserver: Fix incorrect assertion Pedro Alves
@ 2022-03-21 17:04 ` Pedro Alves
0 siblings, 0 replies; 2+ messages in thread
From: Pedro Alves @ 2022-03-21 17:04 UTC (permalink / raw)
To: gdb-patches
On 2022-03-21 16:48, Pedro Alves wrote:
> @@ -1140,11 +1141,11 @@ prepare_resume_reply (char *buf, ptid_t ptid, const target_waitstatus &status)
> An 'S' stop packet always looks like 'Sxx', so all we do
> here is convert the buffer from a T packet to an S packet
> and the avoid adding any extra content by breaking out. */
> - gdb_assert (*buf == 'T');
> - gdb_assert (isxdigit (*(buf + 1)));
> - gdb_assert (isxdigit (*(buf + 2)));
> + gdb_assert (buf_start[0] == 'T');
> + gdb_assert (isxdigit (buf_start[1]));
> + gdb_assert (isxdigit (buf_start[2]));
> *buf = 'S';
> - *(buf + 3) = '\0';
> + buf_start[3] = '\0';
> break;
> }
>
Whoops, the '*buf = 'S';' line is also incorrect, of course. Fixed by this follow up patch.
Pushed to master.
From 4414150d33212f5f395c3bf8a940bccf80ffc508 Mon Sep 17 00:00:00 2001
From: Pedro Alves <pedro@palves.net>
Date: Mon, 21 Mar 2022 16:58:23 +0000
Subject: [PATCH] gdbserver: Fixup previous patch
The previous prepare_resume_reply change missed updating the 'buf'
reference that overwrites the 'T', so if 'buf' was advanced, we'd
still overwrite the wrong character. This fixes it.
Change-Id: Ia8ce433366b85af4e268c1c49e7b447da3130a4d
---
gdbserver/remote-utils.cc | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/gdbserver/remote-utils.cc b/gdbserver/remote-utils.cc
index 0599cc9c4f1..db9b2a66f3c 100644
--- a/gdbserver/remote-utils.cc
+++ b/gdbserver/remote-utils.cc
@@ -1144,7 +1144,7 @@ prepare_resume_reply (char *buf, ptid_t ptid, const target_waitstatus &status)
gdb_assert (buf_start[0] == 'T');
gdb_assert (isxdigit (buf_start[1]));
gdb_assert (isxdigit (buf_start[2]));
- *buf = 'S';
+ buf_start[0] = 'S';
buf_start[3] = '\0';
break;
}
base-commit: 04f0c03a22135c7eefa47ed99c03e5b3dc9a34e2
--
2.26.2
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