On 2023/12/26 20:55, Lianbo Jiang wrote: > On 12/26/23 14:43, devel-request(a)lists.crash-utility.osci.io wrote: > >> Date: Tue, 26 Dec 2023 06:42:55 +0000 >> From: HAGIO KAZUHITO(萩尾　一仁)&lt;k-hagio-ab(a)nec.com&gt; >> Subject: [Crash-utility] Re: [PATCH] x86_64: check bt->bptr before >> calculate framesize >> To: Tao Liu&lt;ltao@redhat.com&gt;,&quot;devel(a)lists.crash-utility.osci.io&quot; >> <devel(a)lists.crash-utility.osci.io&gt; >> Message-ID:<58d63b19-0d8a-3be0-234a-703a4c25dcb9@nec.com> >> Content-Type: text/plain; charset="utf-8" >> >> On 2023/12/26 10:19, Tao Liu wrote: >>> Previously the value of bt->bptr is not checked, which may led to a >>> wrong prev_sp and framesize. As a result, bt->stackbuf[] will be >>> accessed out of range, and segfault. >>> >>> Before: >>> crash> set debug 1 >>> crash> bt >>> ...snip... >>> --- <NMI exception stack> --- >>> #8 [ffffffff9a603e10] __switch_to_asm at ffffffff99800214 >>> rsp: ffffffff9a603e10 textaddr: ffffffff99800214 -> spo: 0 bpo: 0 spr: 0 bpr: 0 type: 0 end: 0 >>> #9 [ffffffff9a603e40] __schedule at ffffffff9960dfb1 >>> rsp: ffffffff9a603e40 textaddr: ffffffff9960dfb1 -> spo: 16 bpo: -16 spr: 4 bpr: 1 type: 0 end: 0 >>> rsp: ffffffff9a603e40 rbp: ffffb9ca076e7ca8 prev_sp: ffffb9ca076e7cb8 framesize: 1829650024 >>> Segmentation fault (core dumped) >>> >>> (gdb) p/x bt->stackbase >>> $1 = 0xffffffff9a600000 >>> (gdb) p/x bt->stacktop >>> $2 = 0xffffffff9a604000 >>> >>> After: >>> crash> set debug 1 >>> crash> bt >>> ...snip... >>> --- <NMI exception stack> --- >>> #8 [ffffffff9a603e10] __switch_to_asm at ffffffff99800214 >>> rsp: ffffffff9a603e10 textaddr: ffffffff99800214 -> spo: 0 bpo: 0 spr: 0 bpr: 0 type: 0 end: 0 >>> #9 [ffffffff9a603e40] __schedule at ffffffff9960dfb1 >>> rsp: ffffffff9a603e40 textaddr: ffffffff9960dfb1 -> spo: 16 bpo: -16 spr: 4 bpr: 1 type: 0 end: 0 >>> #10 [ffffffff9a603e98] schedule_idle at ffffffff9960e87c >>> rsp: ffffffff9a603e98 textaddr: ffffffff9960e87c -> spo: 8 bpo: 0 spr: 5 bpr: 0 type: 0 end: 0 >>> rsp: ffffffff9a603e98 prev_sp: ffffffff9a603ea8 framesize: 0 >>> ...snip... >>> >>> This patch will check bt->bptr value before calculate framesize. Only bt->bptr >>> falls into the range of bt->stackbase and bt->stacktop will be >>> regarded as valid. >>> >>> Signed-off-by: Tao Liu&lt;ltao(a)redhat.com&gt; >>> --- >>> x86_64.c | 3 ++- >>> 1 file changed, 2 insertions(+), 1 deletion(-) >>> >>> diff --git a/x86_64.c b/x86_64.c >>> index 8abe39d..ff1ba6e 100644 >>> --- a/x86_64.c >>> +++ b/x86_64.c >>> @@ -8707,7 +8707,8 @@ x86_64_get_framesize(struct bt_info *bt, ulong textaddr, ulong rsp, char *stack_ >>> if (CRASHDEBUG(1)) >>> fprintf(fp, "rsp: %lx prev_sp: %lx framesize: %d\n", >>> rsp, prev_sp, framesize); >>> - } else if ((korc->sp_reg == ORC_REG_BP) && bt->bptr) { >>> + } else if ((korc->sp_reg == ORC_REG_BP) && bt->bptr && >>> + bt->bptr >= bt->stackbase && bt->bptr <= bt->stacktop) { >> Thank you for looking into this! Looks good to me. >> >> Just a nit, INSTACK() can be used? > > The INSTACK(bt->bptr, bt) is better, let's go with this, Kazu. Tao is on PTO. > > For the patch with the above change: Ack

Thanks, applied with INSTACK(). https://github.com/crash-utility/crash/commit/53d2577cef98b76b122aade9434... Kazu