x86/oops: Show the correct CS value in show_regs() (d38bc89c) · Commits · 戴 / test

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 <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yu-cheng Yu <yu-cheng.yu@intel.com> Link: http://lkml.kernel.org/r/4e36812b6e1e95236a812021d35cbf22746b5af6.1542841400.git.luto@kernel.org Signed-off-by:

Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/process_64.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -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);

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