On Wed, 2011-03-16 at 08:37 -0500, Michael Wolf wrote:
> 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 <[email protected]>
Patch is busted on ppc32 (you add #define's in the middle of a
multi-line macro) and of doubtful stylistic value :-) I'll merge
a slightly reworked variant that includes a new cset comment
with Paulus explanation in it.
Cheers,
Ben.
> ----------
> --- linux-2.6.32-71.el6.ppc64.orig/arch/powerpc/include/asm/ptrace.h
> 2010-08-31 23:56:50.000000000 -0500
> +++ linux-2.6.32-71.el6.ppc64/arch/powerpc/include/asm/ptrace.h
> 2011-03-14 11:43:33.176667099 -0500
> @@ -123,8 +123,14 @@ extern int ptrace_put_reg(struct task_st
> #define TRAP(regs) ((regs)->trap & ~0xF)
> #ifdef __powerpc64__
> #define CHECK_FULL_REGS(regs) BUG_ON(regs->trap & 1)
> +#define PARTIAL_REG_FILL 0xdeadbeefdeadbeefUL
> +#define PARTIAL_REG_START 14
> +#define PARTIAL_REG_END 31
> #else
> #define CHECK_FULL_REGS(regs)
> \
> +#define PARTIAL_REG_FILL 0xdeadbeef
> +#define PARTIAL_REG_START 14
> +#define PARTIAL_REG_END 31
> do { \
> if ((regs)->trap & 1) \
> printk(KERN_CRIT "%s: partial register set\n", __func__); \
> --- linux-2.6.32-71.el6.ppc64.orig/arch/powerpc/kernel/ptrace.c
> 2009-12-02 21:51:21.000000000 -0600
> +++ linux-2.6.32-71.el6.ppc64/arch/powerpc/kernel/ptrace.c 2011-03-14
> 13:01:51.955586126 -0500
> @@ -125,11 +125,16 @@ static int gpr_get(struct task_struct *t
> void *kbuf, void __user *ubuf)
> {
> int ret;
> + int partial_reg;
>
> if (target->thread.regs == NULL)
> return -EIO;
>
> - CHECK_FULL_REGS(target->thread.regs);
> + if (!FULL_REGS(target->thread.regs))
> + /* We have a partial register set. Fill 14-31 with bogus values */
> + for(partial_reg=PARTIAL_REG_START;partial_reg <= PARTIAL_REG_END;
> + partial_reg++)
> + target->thread.regs->gpr[partial_reg] = PARTIAL_REG_FILL;
>
> ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> target->thread.regs,
> @@ -536,11 +541,16 @@ static int gpr32_get(struct task_struct
> compat_ulong_t *k = kbuf;
> compat_ulong_t __user *u = ubuf;
> compat_ulong_t reg;
> + int partial_reg;
>
> if (target->thread.regs == NULL)
> return -EIO;
>
> - CHECK_FULL_REGS(target->thread.regs);
> + if (!FULL_REGS(target->thread.regs))
> + /* We have a partial register set. Fill 14-31 with bogus values */
> + for(partial_reg=PARTIAL_REG_START;partial_reg <= PARTIAL_REG_END;
> + partial_reg++)
> + target->thread.regs->gpr[partial_reg] = PARTIAL_REG_FILL;
>
> pos /= sizeof(reg);
> count /= sizeof(reg);
>
>
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