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authorKarimAllah Ahmed <karahmed@amazon.de>2015-06-30 14:57:39 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-06-30 19:44:57 -0700
commita846f47962e4643b33847c9a0b2b6387f02a93be (patch)
treef3764eb180def4a5194d11be45b80fc40fb920a0
parent460b865e53c347ebf110e50d499718cd9b39d810 (diff)
x86/kexec: prepend elfcorehdr instead of appending it to the crash-kernel command-line.
Any parameter passed after '--' in the kernel command-line will not be parsed by the kernel at all, instead it will be passed directly to init process. Currently the kernel appends elfcorehdr=<paddr> to the cmdline passed from kexec load, and if this command-line is used to pass parameters to init process this means that 'elfcorehdr' will not be parsed as a kernel parameter at all which will be a problem for vmcore subsystem since it will know nothing about the location of the ELF structure! Prepending 'elfcorehdr' instead of appending it fixes this problem since it ensures that it always comes before '--' and so it's always parsed as a kernel command-line parameter. Even with this patch things can still go wrong if 'CONFIG_CMDLINE' was also used to embedd a command-line to the crash dump kernel and this command-line contains '--' since the current behavior of the kernel is to actually append the boot loader command-line to the embedded command-line. Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Cc: Haren Myneni <hbabu@us.ibm.com> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--arch/x86/kernel/kexec-bzimage64.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index ca05f86481aa..ca83f7ac388b 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -72,15 +72,16 @@ static int setup_cmdline(struct kimage *image, struct boot_params *params,
unsigned long cmdline_len)
{
char *cmdline_ptr = ((char *)params) + cmdline_offset;
- unsigned long cmdline_ptr_phys, len;
+ unsigned long cmdline_ptr_phys, len = 0;
uint32_t cmdline_low_32, cmdline_ext_32;
- memcpy(cmdline_ptr, cmdline, cmdline_len);
if (image->type == KEXEC_TYPE_CRASH) {
- len = sprintf(cmdline_ptr + cmdline_len - 1,
- " elfcorehdr=0x%lx", image->arch.elf_load_addr);
- cmdline_len += len;
+ len = sprintf(cmdline_ptr,
+ "elfcorehdr=0x%lx ", image->arch.elf_load_addr);
}
+ memcpy(cmdline_ptr + len, cmdline, cmdline_len);
+ cmdline_len += len;
+
cmdline_ptr[cmdline_len - 1] = '\0';
pr_debug("Final command line is: %s\n", cmdline_ptr);