Re: [Crash-utility] [PATCH] x86_64: Fix that Particular kvaddr is converted to wrong paddr (RHEL6 x86_64)

----- Original Message ----- >> 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. > > What is check/macro? How do we check what? > Certainly, these addresses are vsyscall region. > After applying this patch, crash looks read vsyscall region correctly. The vsyscall-region check fits more naturally in the x86_64_IS_VMALLOC_ADDR() function, along with all of the other checks for non-unity-mapped addresses. Queued for crash-7.1.5: https://github.com/crash-utility/crash/commit/2e29d684a4583a45ae3c9b16014... Thanks for the report, Dave > > > > crash> sym vsyscall > // abbreviation // > ffffffffff600000 (t) .vsyscall_0 > ffffffffff600140 (t) .vsyscall_fn > ffffffffff600180 (d) .vsyscall_gtod_data > ffffffffff600180 (D) __vsyscall_gtod_data > ffffffffff600400 (t) .vsyscall_1 > ffffffffff600800 (t) .vsyscall_2 > ffffffffff700680 (A) VDSO64_vsyscall_gtod_data > > crash> sym VDSO > symbol not found: VDSO > possible alternatives: > ffffffffff700000 (A) VDSO64_PRELINK > ffffffffff700670 (A) VDSO64_jiffies > ffffffffff700678 (A) VDSO64_vgetcpu_mode > ffffffffff700680 (A) VDSO64_vsyscall_gtod_data > > > //////// not patched ///////// > crash> dis .vsyscall_0 > 0xffffffffff600000 <.vsyscall_0>: add %al,(%rax) > 0xffffffffff600002 <vgettimeofday+2>: add %al,(%rax) > 0xffffffffff600004 <vgettimeofday+4>: add %al,(%rax) > 0xffffffffff600006 <vgettimeofday+6>: add %al,(%rax) > 0xffffffffff600008 <vgettimeofday+8>: add %al,(%rax) > 0xffffffffff60000a <vgettimeofday+10>: add %al,(%rax) > // abbreviation // > > > //////// after applying this patch ///////// > crash> dis .vsyscall_0 > 0xffffffffff600000 <.vsyscall_0>: push %rbp > 0xffffffffff600001 <vgettimeofday+1>: mov %rsp,%rbp > 0xffffffffff600004 <vgettimeofday+4>: push %r13 > 0xffffffffff600006 <vgettimeofday+6>: push %r12 > 0xffffffffff600008 <vgettimeofday+8>: mov %rdi,%r12 > 0xffffffffff60000b <vgettimeofday+11>: push %rbx > 0xffffffffff60000c <vgettimeofday+12>: mov %rsi,%rbx > 0xffffffffff60000f <vgettimeofday+15>: sub $0x8,%rsp > 0xffffffffff600013 <vgettimeofday+19>: test %rdi,%rdi > 0xffffffffff600016 <vgettimeofday+22>: je 0xffffffffff6000d5 > <vgettimeofday+213> > // abbreviation // > > > On 2015/12/22 22:42, Dave Anderson wrote: >> >> >> ----- 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&gt; >>> 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&gt; >>> Signed-off-by: Nakajima Akira <nakajima.akira(a)nttcom.co.jp&gt; >>> >>> --- >>> 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 >>> >>> >>> -- >>> Crash-utility mailing list >>> Crash-utility(a)redhat.com >>> https://www.redhat.com/mailman/listinfo/crash-utility >> >> -- >> Crash-utility mailing list >> Crash-utility(a)redhat.com >> https://www.redhat.com/mailman/listinfo/crash-utility >> . >> > > -- > Crash-utility mailing list > Crash-utility(a)redhat.com > https://www.redhat.com/mailman/listinfo/crash-utility > -- Crash-utility mailing list Crash-utility(a)redhat.com https://www.redhat.com/mailman/listinfo/crash-utility .