Commit-ID: ab513927ab449af00cc70b0269e15ee80dd537f9 Gitweb: http://git.kernel.org/tip/ab513927ab449af00cc70b0269e15ee80dd537f9 Author: Andy Lutomirski <luto@xxxxxxxxxx> AuthorDate: Thu, 30 Jul 2015 20:32:41 -0700 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Tue, 4 Aug 2015 10:16:54 +0200 perf/x86/hw_breakpoints: Improve range breakpoint validation Range breakpoints will do the wrong thing if the address isn't aligned. While we're there, add comments about why it's safe for instruction breakpoints. Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Brian Gerst <brgerst@xxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/ae25d14d61f2f43b78e0a247e469f3072df7e201.1438312874.git.luto@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/kernel/hw_breakpoint.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c index 78f3e90..6f345d3 100644 --- a/arch/x86/kernel/hw_breakpoint.c +++ b/arch/x86/kernel/hw_breakpoint.c @@ -291,8 +291,18 @@ static int arch_build_bp_info(struct perf_event *bp) break; #endif default: + /* AMD range breakpoint */ if (!is_power_of_2(bp->attr.bp_len)) return -EINVAL; + if (bp->attr.bp_addr & (bp->attr.bp_len - 1)) + return -EINVAL; + /* + * It's impossible to use a range breakpoint to fake out + * user vs kernel detection because bp_len - 1 can't + * have the high bit set. If we ever allow range instruction + * breakpoints, then we'll have to check for kprobe-blacklisted + * addresses anywhere in the range. + */ if (!cpu_has_bpext) return -EOPNOTSUPP; info->mask = bp->attr.bp_len - 1; -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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