From 57745c903f78ffdb10a6198a6e35e5a1e63ea4b0 Mon Sep 17 00:00:00 2001
From: Pedro Alves <palves@redhat.com>
Date: Tue, 15 Jul 2014 16:22:14 +0100
Subject: [PATCH] [GDB/Linux] Avoid stale errno
The fix that went into GDBserver is also needed on the GDB side.
Although most compilers follow right-to-left evaluation order, the
order of evaluation of a function call's arguments is really
unspecified. target_pid_to_str may well clobber errno when we get to
evaluate the third argument to fprintf_unfiltered.
gdb/
2014-07-15 Pedro Alves <palves@redhat.com>
* linux-nat.c (kill_callback): Save errno and work with saved
copy.
---
gdb/ChangeLog | 5 +++++
gdb/linux-nat.c | 24 ++++++++++++++++--------
2 files changed, 21 insertions(+), 8 deletions(-)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 157dc4933e8..2b6604bf3c6 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2014-07-15 Pedro Alves <palves@redhat.com>
+
+ * linux-nat.c (kill_callback): Save errno and work with saved
+ copy.
+
2014-07-15 Simon Marchi <simon.marchi@ericsson.com>
* expprint.c (dump_subexp_body_standard): Handle OP_STRING.
diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
index 0ab0362f1ec..c738abf9f3e 100644
--- a/gdb/linux-nat.c
+++ b/gdb/linux-nat.c
@@ -3706,20 +3706,28 @@ kill_callback (struct lwp_info *lp, void *data)
errno = 0;
kill (ptid_get_lwp (lp->ptid), SIGKILL);
if (debug_linux_nat)
- fprintf_unfiltered (gdb_stdlog,
- "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
- target_pid_to_str (lp->ptid),
- errno ? safe_strerror (errno) : "OK");
+ {
+ int save_errno = errno;
+
+ fprintf_unfiltered (gdb_stdlog,
+ "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
+ target_pid_to_str (lp->ptid),
+ save_errno ? safe_strerror (save_errno) : "OK");
+ }
/* Some kernels ignore even SIGKILL for processes under ptrace. */
errno = 0;
ptrace (PTRACE_KILL, ptid_get_lwp (lp->ptid), 0, 0);
if (debug_linux_nat)
- fprintf_unfiltered (gdb_stdlog,
- "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
- target_pid_to_str (lp->ptid),
- errno ? safe_strerror (errno) : "OK");
+ {
+ int save_errno = errno;
+
+ fprintf_unfiltered (gdb_stdlog,
+ "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
+ target_pid_to_str (lp->ptid),
+ save_errno ? safe_strerror (save_errno) : "OK");
+ }
return 0;
}
--
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