From: Xunlei Pang <xlpang@redhat.com> To: linux-kernel@vger.kernel.org, kexec@lists.infradead.org Cc: akpm@linux-foundation.org, Eric Biederman <ebiederm@xmission.com>, Dave Young <dyoung@redhat.com>, Baoquan He <bhe@redhat.com>, Xunlei Pang <xlpang@redhat.com> Subject: [PATCH] kexec: Update vmcoreinfo after crash happened Date: Thu, 16 Mar 2017 20:16:27 +0800 [thread overview] Message-ID: <1489666587-24103-1-git-send-email-xlpang@redhat.com> (raw) Currently vmcoreinfo data is updated at boot time subsys_initcall(), it has the risk of being modified by some wrong code during system is running. As a result, vmcore dumped will contain the wrong vmcoreinfo. Later on, when using "crash" utility to parse this vmcore, we probably will get "Segmentation fault". Based on the fact that the value of each vmcoreinfo stays invariable once kernel boots up, we safely move all the vmcoreinfo operations into crash_save_vmcoreinfo() which is called after crash happened. In this way, vmcoreinfo data correctness is always guaranteed. Signed-off-by: Xunlei Pang <xlpang@redhat.com> --- kernel/kexec_core.c | 14 +++----------- 1 file changed, 3 insertions(+), 11 deletions(-) diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index bfe62d5..1bfdd96 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -1367,12 +1367,6 @@ static void update_vmcoreinfo_note(void) final_note(buf); } -void crash_save_vmcoreinfo(void) -{ - vmcoreinfo_append_str("CRASHTIME=%ld\n", get_seconds()); - update_vmcoreinfo_note(); -} - void vmcoreinfo_append_str(const char *fmt, ...) { va_list args; @@ -1402,7 +1396,7 @@ phys_addr_t __weak paddr_vmcoreinfo_note(void) return __pa_symbol((unsigned long)(char *)&vmcoreinfo_note); } -static int __init crash_save_vmcoreinfo_init(void) +void crash_save_vmcoreinfo(void) { VMCOREINFO_OSRELEASE(init_uts_ns.name.release); VMCOREINFO_PAGESIZE(PAGE_SIZE); @@ -1474,13 +1468,11 @@ static int __init crash_save_vmcoreinfo_init(void) #endif arch_crash_save_vmcoreinfo(); - update_vmcoreinfo_note(); + vmcoreinfo_append_str("CRASHTIME=%ld\n", get_seconds()); - return 0; + update_vmcoreinfo_note(); } -subsys_initcall(crash_save_vmcoreinfo_init); - /* * Move into place and start executing a preloaded standalone * executable. If nothing was preloaded return an error. -- 1.8.3.1
WARNING: multiple messages have this Message-ID (diff)
From: Xunlei Pang <xlpang@redhat.com> To: linux-kernel@vger.kernel.org, kexec@lists.infradead.org Cc: Xunlei Pang <xlpang@redhat.com>, akpm@linux-foundation.org, Dave Young <dyoung@redhat.com>, Eric Biederman <ebiederm@xmission.com>, Baoquan He <bhe@redhat.com> Subject: [PATCH] kexec: Update vmcoreinfo after crash happened Date: Thu, 16 Mar 2017 20:16:27 +0800 [thread overview] Message-ID: <1489666587-24103-1-git-send-email-xlpang@redhat.com> (raw) Currently vmcoreinfo data is updated at boot time subsys_initcall(), it has the risk of being modified by some wrong code during system is running. As a result, vmcore dumped will contain the wrong vmcoreinfo. Later on, when using "crash" utility to parse this vmcore, we probably will get "Segmentation fault". Based on the fact that the value of each vmcoreinfo stays invariable once kernel boots up, we safely move all the vmcoreinfo operations into crash_save_vmcoreinfo() which is called after crash happened. In this way, vmcoreinfo data correctness is always guaranteed. Signed-off-by: Xunlei Pang <xlpang@redhat.com> --- kernel/kexec_core.c | 14 +++----------- 1 file changed, 3 insertions(+), 11 deletions(-) diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index bfe62d5..1bfdd96 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -1367,12 +1367,6 @@ static void update_vmcoreinfo_note(void) final_note(buf); } -void crash_save_vmcoreinfo(void) -{ - vmcoreinfo_append_str("CRASHTIME=%ld\n", get_seconds()); - update_vmcoreinfo_note(); -} - void vmcoreinfo_append_str(const char *fmt, ...) { va_list args; @@ -1402,7 +1396,7 @@ phys_addr_t __weak paddr_vmcoreinfo_note(void) return __pa_symbol((unsigned long)(char *)&vmcoreinfo_note); } -static int __init crash_save_vmcoreinfo_init(void) +void crash_save_vmcoreinfo(void) { VMCOREINFO_OSRELEASE(init_uts_ns.name.release); VMCOREINFO_PAGESIZE(PAGE_SIZE); @@ -1474,13 +1468,11 @@ static int __init crash_save_vmcoreinfo_init(void) #endif arch_crash_save_vmcoreinfo(); - update_vmcoreinfo_note(); + vmcoreinfo_append_str("CRASHTIME=%ld\n", get_seconds()); - return 0; + update_vmcoreinfo_note(); } -subsys_initcall(crash_save_vmcoreinfo_init); - /* * Move into place and start executing a preloaded standalone * executable. If nothing was preloaded return an error. -- 1.8.3.1 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
next reply other threads:[~2017-03-16 12:15 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-03-16 12:16 Xunlei Pang [this message] 2017-03-16 12:16 ` [PATCH] kexec: Update vmcoreinfo after crash happened Xunlei Pang 2017-03-16 12:27 ` Baoquan He 2017-03-16 12:27 ` Baoquan He 2017-03-16 12:36 ` Xunlei Pang 2017-03-16 12:36 ` Xunlei Pang 2017-03-16 13:18 ` Baoquan He 2017-03-16 13:18 ` Baoquan He 2017-03-16 13:40 ` Xunlei Pang 2017-03-16 13:40 ` Xunlei Pang 2017-03-18 18:23 ` Petr Tesarik 2017-03-18 18:23 ` Petr Tesarik 2017-03-20 2:17 ` Xunlei Pang 2017-03-20 2:17 ` Xunlei Pang 2017-03-20 13:04 ` Petr Tesarik 2017-03-20 13:04 ` Petr Tesarik 2017-03-20 19:15 ` Eric W. Biederman 2017-03-20 19:15 ` Eric W. Biederman 2017-03-21 2:05 ` Xunlei Pang 2017-03-21 2:05 ` Xunlei Pang
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