From 11cb8762fcacf259f9d7707201daba6670d1946a Mon Sep 17 00:00:00 2001 From: Joel Brobecker Date: Thu, 29 Aug 2013 21:02:15 +0000 Subject: [PATCH] thread support broken on ppc-aix. Thread support got broken when adding 64bit support on ppc-aix. Upon digging further, I found that the following patch... | * gdb_ptrace.h: Use ptrace64 instead of ptrace if HAVE_PTRACE64 | is defined. | * rs6000-nat.c: Check for __ld_info64_ if compiling 64 BIT gdb. | (rs6000_ptrace32): Call ptrace64 instead of ptrace if present. | (rs6000_ptrace64): Call ptace64 instead of ptracex if present. | * configure.ac: Check for ptrace64. | * configure, config.in: Regenerate. ... is responsible for this regression: (gdb) x /x &__n_pthreads 0xf06a8258 <__n_pthreads>: Cannot access memory at address 0xf06a8258 Prior to the patch, we have: (gdb) x /x &__n_pthreads 0xf06a8258 <__n_pthreads>: 0x00000003 The problem occurs inside rs6000_ptrace32, while calling ptrace64. The address is given to rs6000_ptrace32 as an "int *", while ptrace64 takes a "long long". The cast causes the address to be sign-extended, which results in GDB trying to read the wrong address. This patch fixes the issue by casting the address to a "uintptr_t" instead, and letting the compiler do the implicit conversion to "long long" in the function call. gdb/ChangeLog: * rs6000-nat.c (rs6000_ptrace32): Cast "addr" to "uintptr_t" instead of "long long" in call to ptrace64. --- gdb/ChangeLog | 5 +++++ gdb/rs6000-nat.c | 2 +- 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 7c2647e317..f676c3f3ea 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2013-08-29 Joel Brobecker + + * rs6000-nat.c (rs6000_ptrace32): Cast "addr" to "uintptr_t" + instead of "long long" in call to ptrace64. + 2013-08-29 Andrew Burgess * mi/mi-interp.c (mi_command_loop): Change signature to match diff --git a/gdb/rs6000-nat.c b/gdb/rs6000-nat.c index 804b31680b..374976e25a 100644 --- a/gdb/rs6000-nat.c +++ b/gdb/rs6000-nat.c @@ -132,7 +132,7 @@ static int rs6000_ptrace32 (int req, int id, int *addr, int data, int *buf) { #ifdef HAVE_PTRACE64 - int ret = ptrace64 (req, id, (long long) addr, data, buf); + int ret = ptrace64 (req, id, (uintptr_t) addr, data, buf); #else int ret = ptrace (req, id, (int *)addr, data, buf); #endif