From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: mjw@us.ibm.com
Cc: linuxppc-dev@ozlabs.org, mikey@neuling.org, anton@samba.org
Subject: Re: [PATCH v2] powerpc/ptrace: remove BUG_ON when full register set not available
Date: Mon, 21 Mar 2011 11:15:54 +1100 [thread overview]
Message-ID: <1300666554.2402.88.camel@pasglop> (raw)
In-Reply-To: <1300282642.15145.2.camel@w500>
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 <mjw@linux.vnet.ibm.com>
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);
>
>
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
prev parent reply other threads:[~2011-03-21 0:16 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-16 13:37 [PATCH v2] powerpc/ptrace: remove BUG_ON when full register set not available Michael Wolf
2011-03-17 4:20 ` Paul Mackerras
2011-03-21 0:15 ` Benjamin Herrenschmidt [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1300666554.2402.88.camel@pasglop \
--to=benh@kernel.crashing.org \
--cc=anton@samba.org \
--cc=linuxppc-dev@ozlabs.org \
--cc=mikey@neuling.org \
--cc=mjw@us.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).