Fix a kprobes bug in JNG/JNLE emulation when a kprobe is

installed at such instructions, possibly resulting in
 incorrect execution (the wrong branch taken).
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'perf-urgent-2022-08-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 kprobes fix from Ingo Molnar:
 "Fix a kprobes bug in JNG/JNLE emulation when a kprobe is installed at
  such instructions, possibly resulting in incorrect execution (the
  wrong branch taken)"

* tag 'perf-urgent-2022-08-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/kprobes: Fix JNG/JNLE emulation
This commit is contained in:
Linus Torvalds 2022-08-21 15:01:51 -07:00
commit 4f61f842d1

View File

@ -505,7 +505,7 @@ static void kprobe_emulate_jcc(struct kprobe *p, struct pt_regs *regs)
match = ((regs->flags & X86_EFLAGS_SF) >> X86_EFLAGS_SF_BIT) ^
((regs->flags & X86_EFLAGS_OF) >> X86_EFLAGS_OF_BIT);
if (p->ainsn.jcc.type >= 0xe)
match = match && (regs->flags & X86_EFLAGS_ZF);
match = match || (regs->flags & X86_EFLAGS_ZF);
}
__kprobe_emulate_jmp(p, regs, (match && !invert) || (!match && invert));
}