From d38bc89c72e7235ac889ae64fe7828e2e61a18af Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Wed, 21 Nov 2018 15:11:24 -0800 Subject: [PATCH] x86/oops: Show the correct CS value in show_regs() show_regs() shows the CS in the CPU register instead of the value in regs. This means that we'll probably print "CS: 0010" almost all the time regardless of what was actually in CS when the kernel malfunctioned. This gives a particularly confusing result if we OOPSed due to an implicit supervisor access from user mode. Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Cc: Yu-cheng Yu Link: http://lkml.kernel.org/r/4e36812b6e1e95236a812021d35cbf22746b5af6.1542841400.git.luto@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/kernel/process_64.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 0e0b428..2b8e632 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -66,7 +66,7 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode) unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L, fs, gs, shadowgs; unsigned long d0, d1, d2, d3, d6, d7; unsigned int fsindex, gsindex; - unsigned int ds, cs, es; + unsigned int ds, es; show_iret_regs(regs); @@ -98,7 +98,6 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode) } asm("movl %%ds,%0" : "=r" (ds)); - asm("movl %%cs,%0" : "=r" (cs)); asm("movl %%es,%0" : "=r" (es)); asm("movl %%fs,%0" : "=r" (fsindex)); asm("movl %%gs,%0" : "=r" (gsindex)); @@ -114,7 +113,7 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode) printk(KERN_DEFAULT "FS: %016lx(%04x) GS:%016lx(%04x) knlGS:%016lx\n", fs, fsindex, gs, gsindex, shadowgs); - printk(KERN_DEFAULT "CS: %04x DS: %04x ES: %04x CR0: %016lx\n", cs, ds, + printk(KERN_DEFAULT "CS: %04lx DS: %04x ES: %04x CR0: %016lx\n", regs->cs, ds, es, cr0); printk(KERN_DEFAULT "CR2: %016lx CR3: %016lx CR4: %016lx\n", cr2, cr3, cr4); -- 2.7.4