Re: [Crash-utility] [PATCH] x86_64: Fix that Particular kvaddr is converted to wrong paddr (RHEL6 x86_64)
----- Original Message -----
I didn't check XEN HYPER MODE, I don't have XEN.
If we need similar statement "if (kvaddr < MODULES_END)"
please add inside in "if (XEN_HYPER_MODE())" (1859@x86_64_kvtop)
>From ed300b74998e0923313e4fd14b9a41e305942b44 Mon Sep 17 00:00:00 2001
From: Nakajima Akira <nakajima.akira(a)nttcom.co.jp>
Date: Tue, 22 Dec 2015 15:46:42 +0900
Subject: [PATCH] Fix that particular kvaddr is converted to wrong paddr
BUG INFO
Particular kvaddr is converted to wrong paddr.
You can see this bug on RHEL6_x86_64. (at present only RHEL6)
(I checked RHEL5, RHEL7, Fedora21, Fedora23)
I am out of the office until January 4th (only checking email until then), and will not
be able to look into this until then. But because it is such a fundamental change that
you are proposing, it might make sense to create a check/macro that is specific to
the vsyscall region.
Thanks,
Dave
from /proc/kallsyms
ffffffffff6008c0 D __jiffies
/////////// wrong ///////////
crash> vtop ffffffffff6008c0
VIRTUAL PHYSICAL
ffffffffff6008c0 7f6008c0
PAGE PHYSICAL MAPPING INDEX CNT FLAGS
ffffea00000623b8 1c11000 0 0 1 20000000000400
reserved
crash> rd ffffffffff6008c0
ffffffffff6008c0: 0000000000000000 ........
/////////// correct ///////////
crash> vtop ffffffffff6008c0
VIRTUAL PHYSICAL
ffffffffff6008c0 1c118c0
PAGE PHYSICAL MAPPING INDEX CNT FLAGS
ffffea00000623b8 1c11000 0 0 1 20000000000400
reserved
crash> rd ffffffffff6008c0
ffffffffff6008c0: 00000000ffffe43a :.......
Reported-by: Nakajima Akira <nakajima.akira(a)nttcom.co.jp>
Signed-off-by: Nakajima Akira <nakajima.akira(a)nttcom.co.jp>
---
x86_64.c | 28 +++++++++++++++-------------
1 files changed, 15 insertions(+), 13 deletions(-)
diff --git a/x86_64.c b/x86_64.c
index ff6fdd5..dab4d43 100644
--- a/x86_64.c
+++ b/x86_64.c
@@ -1872,19 +1872,21 @@ x86_64_kvtop(struct task_context *tc, ulong kvaddr,
physaddr_t *paddr, int verbo
fprintf(fp, "PAGE DIRECTORY: %lx\n", *pml4);
}
} else {
- if (!vt->vmalloc_start) {
- *paddr = x86_64_VTOP(kvaddr);
- return TRUE;
- }
-
- if (!IS_VMALLOC_ADDR(kvaddr)) {
- *paddr = x86_64_VTOP(kvaddr);
- if (!verbose)
- return TRUE;
- }
-
- if (XEN() && (kt->xen_flags & WRITABLE_PAGE_TABLES))
- return (x86_64_kvtop_xen_wpt(tc, kvaddr, paddr, verbose));
+ if (kvaddr < MODULES_END) {
+ if (!vt->vmalloc_start) {
+ *paddr = x86_64_VTOP(kvaddr);
+ return TRUE;
+ }
+
+ if (!IS_VMALLOC_ADDR(kvaddr)) {
+ *paddr = x86_64_VTOP(kvaddr);
+ if (!verbose)
+ return TRUE;
+ }
+
+ if (XEN() && (kt->xen_flags & WRITABLE_PAGE_TABLES))
+ return (x86_64_kvtop_xen_wpt(tc, kvaddr, paddr, verbose));
+ }
/*
* pgd = pgd_offset_k(addr);
--
1.7.1
--
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