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| Started by | Andy Lutomirski <luto@kernel.org> |
|---|---|
| First post | 2015-07-31 05:40 +0200 |
| Last post | 2015-08-04 11:00 +0200 |
| Articles | 2 — 2 participants |
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[PATCH 2/3] x86/perf/hw_breakpoint: Improve range breakpoint validation Andy Lutomirski <luto@kernel.org> - 2015-07-31 05:40 +0200
[tip:perf/core] perf/x86/hw_breakpoints: Improve range breakpoint validation tip-bot for Andy Lutomirski <tipbot@zytor.com> - 2015-08-04 11:00 +0200
| From | Andy Lutomirski <luto@kernel.org> |
|---|---|
| Date | 2015-07-31 05:40 +0200 |
| Subject | [PATCH 2/3] x86/perf/hw_breakpoint: Improve range breakpoint validation |
| Message-ID | <pS9kR-1Uh-1@gated-at.bofh.it> |
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@kernel.org> --- 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 78f3e90c5659..6f345d302cf6 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; -- 2.4.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | tip-bot for Andy Lutomirski <tipbot@zytor.com> |
|---|---|
| Date | 2015-08-04 11:00 +0200 |
| Subject | [tip:perf/core] perf/x86/hw_breakpoints: Improve range breakpoint validation |
| Message-ID | <pTGeK-5Af-23@gated-at.bofh.it> |
| In reply to | #1196565 |
Commit-ID: ab513927ab449af00cc70b0269e15ee80dd537f9 Gitweb: http://git.kernel.org/tip/ab513927ab449af00cc70b0269e15ee80dd537f9 Author: Andy Lutomirski <luto@kernel.org> AuthorDate: Thu, 30 Jul 2015 20:32:41 -0700 Committer: Ingo Molnar <mingo@kernel.org> 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@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/ae25d14d61f2f43b78e0a247e469f3072df7e201.1438312874.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> --- 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-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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