From: Michael Wolf <mjw@linux.vnet.ibm.com>
To: linuxppc-dev@ozlabs.org
Cc: mikey@neuling.org, anton@samba.org
Subject: [PATCH] powerpc/ptrace: remove BUG_ON when full register set not available
Date: Tue, 01 Mar 2011 14:26:44 -0600 [thread overview]
Message-ID: <1299011204.28753.8.camel@w500> (raw)
In some cases during a threaded core dump not all
the threads will have a full register set. This
will cause problems when the sigkill is sent to
the thread. To solve this problem a poison value
(0xdeadbeef) will be placed in the buffer in place
of the actual register values. This will affect
gpr14 to gpr31.
Signed-off-by: Mike Wolf <mjw@linux.vnet.ibm.com>
----------
--- ptracev2.orig/include/linux/regset.h 2011-02-20 12:15:57.000000000 -0600
+++ ptracev2/include/linux/regset.h 2011-02-28 13:33:36.685302349 -0600
@@ -240,6 +240,34 @@ static inline int user_regset_copyout(un
}
return 0;
}
+/* want the count to be the registers 14-31 inclusive */
+#define POISON_REG_CNT (PT_R31-PT_R14+1)
+static inline int user_regset_copyout_poison(unsigned int *pos,
+ unsigned int *count,
+ void **kbuf, void __user **ubuf,
+ const int start_pos,
+ const int end_pos)
+{
+ long poison_data[POISON_REG_CNT] = { [0 ... POISON_REG_CNT-1] = 0xdeadbeefdeadbeefUL };
+
+ if (*count == 0)
+ return 0;
+ BUG_ON(*pos < start_pos);
+ if (end_pos < 0 || *pos < end_pos) {
+ unsigned int copy = (end_pos < 0 ? *count
+ : min(*count, end_pos - *pos));
+ if (*kbuf) {
+ memset(*kbuf, 0xdeadbeef, copy);
+ *kbuf += copy;
+ } else if (__copy_to_user(*ubuf,poison_data, copy))
+ return -EFAULT;
+ else
+ *ubuf += copy;
+ *pos += copy;
+ *count -= copy;
+ }
+ return 0;
+}
static inline int user_regset_copyin(unsigned int *pos, unsigned int *count,
const void **kbuf,
--- ptracev2.orig/arch/powerpc/kernel/ptrace.c 2011-02-20 12:15:57.000000000 -0600
+++ ptracev2/arch/powerpc/kernel/ptrace.c 2011-03-01 13:49:12.686354353 -0600
@@ -234,11 +234,29 @@ static int gpr_get(struct task_struct *t
if (target->thread.regs == NULL)
return -EIO;
- CHECK_FULL_REGS(target->thread.regs);
- ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
- target->thread.regs,
- 0, offsetof(struct pt_regs, msr));
+ if (!FULL_REGS(target->thread.regs)) {
+ /* Don't have the full register set. Copy out register r0-r13 */
+ ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+ target->thread.regs,
+ 0, sizeof(long)*PT_R14);
+
+ /* Dont want to change the actual register values so rather than read the */
+ /* actual register copy a poison value into the buffer instead */
+ if (!ret)
+ ret = user_regset_copyout_poison(&pos, &count, &kbuf, &ubuf,
+ sizeof(long)*PT_R14, offsetof(struct pt_regs, nip));
+
+ /* Copy out the rest of the registers as usual */
+ if (!ret)
+ ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+ target->thread.regs,
+ offsetof(struct pt_regs, nip), offsetof(struct pt_regs, msr));
+
+ } else
+ ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+ target->thread.regs,
+ 0, offsetof(struct pt_regs, msr));
if (!ret) {
unsigned long msr = get_user_msr(target);
ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &msr,
@@ -645,11 +663,29 @@ static int gpr32_get(struct task_struct
if (target->thread.regs == NULL)
return -EIO;
- CHECK_FULL_REGS(target->thread.regs);
-
pos /= sizeof(reg);
count /= sizeof(reg);
+ if(!FULL_REGS(target->thread.regs)) {
+ if (kbuf) {
+ /* Don't have the full register set. Copy out register r0-r13 */
+ for (; count > 0 && pos < PT_R14; --count)
+ *k++ = regs[pos++];
+
+ /* Dont want to change the actual register values so rather than read the */
+ /* actual register copy a poison value into the buffer instead */
+ for (; count > 0 && pos <= PT_R31; --count,pos++)
+ *k++ = 0xdeadbeef;
+
+ } else {
+ for (; count > 0 && pos < PT_R14; --count)
+ if (__put_user((compat_ulong_t) regs[pos++], u++))
+ return -EFAULT;
+ for (; count > 0 && pos <= PT_R31; --count,pos++)
+ if (__put_user((compat_ulong_t) 0xdeadbeef, u++))
+ return -EFAULT;
+ }
+ }
if (kbuf)
for (; count > 0 && pos < PT_MSR; --count)
*k++ = regs[pos++];
next reply other threads:[~2011-03-01 20:26 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-01 20:26 Michael Wolf [this message]
2011-03-02 3:08 ` [PATCH] powerpc/ptrace: remove BUG_ON when full register set not available Benjamin Herrenschmidt
2011-03-02 15:44 ` Michael Wolf
2011-03-21 0:18 [PATCH] powerpc/ptrace: Remove " Benjamin Herrenschmidt
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