From b430f7c4706aeba4270c7ab7744fc504b9315e1c Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Jun 2012 15:30:31 +0200 Subject: perf/x86: Fix Intel shared extra MSR allocation Zheng Yan reported that event group validation can wreck event state when Intel extra_reg allocation changes event state. Validation shouldn't change any persistent state. Cloning events in validate_{event,group}() isn't really pretty either, so add a few special cases to avoid modifying the event state. The code is restructured to minimize the special case impact. Reported-by: Zheng Yan Acked-by: Stephane Eranian Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1338903031.28282.175.camel@twins Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event.c | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/x86/kernel/cpu/perf_event.c') diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index e049d6da018..cb608383e4f 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -1496,6 +1496,7 @@ static struct cpu_hw_events *allocate_fake_cpuc(void) if (!cpuc->shared_regs) goto error; } + cpuc->is_fake = 1; return cpuc; error: free_fake_cpuc(cpuc); -- cgit v1.2.2 From 302fa4b58ac754a6da13f4f5546f710fecc3b945 Mon Sep 17 00:00:00 2001 From: Arun Sharma Date: Fri, 20 Apr 2012 15:41:33 -0700 Subject: perf/x86: Allow multiple stacks Without this patch, applications with two different stack regions (eg: native stack vs JIT stack) get truncated callchains even when RBP chaining is present. GDB shows proper stack traces and the frame pointer chaining is intact. This patch disables the (fp < RSP) check, hoping that other checks in the code save the day for us. In our limited testing, this didn't seem to break anything. In the long term, we could potentially have userspace advise the kernel on the range of valid stack addresses, so we don't spend a lot of time unwinding from bogus addresses. Signed-off-by: Arun Sharma CC: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker Cc: Mike Galbraith Cc: Paul Mackerras Cc: Stephane Eranian Cc: Namhyung Kim Cc: Tom Zanussi Cc: linux-kernel@vger.kernel.org Cc: linux-perf-users@vger.kernel.org Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1334961696-19580-2-git-send-email-asharma@fb.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event.c | 6 ------ 1 file changed, 6 deletions(-) (limited to 'arch/x86/kernel/cpu/perf_event.c') diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index cb608383e4f..e78bc256aea 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -1781,9 +1781,6 @@ perf_callchain_user32(struct pt_regs *regs, struct perf_callchain_entry *entry) if (bytes != sizeof(frame)) break; - if (fp < compat_ptr(regs->sp)) - break; - perf_callchain_store(entry, frame.return_address); fp = compat_ptr(frame.next_frame); } @@ -1827,9 +1824,6 @@ perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs) if (bytes != sizeof(frame)) break; - if ((unsigned long)fp < regs->sp) - break; - perf_callchain_store(entry, frame.return_address); fp = frame.next_frame; } -- cgit v1.2.2 From bc6ca7b342d5ae15c3ba3081fd40271b8039fb25 Mon Sep 17 00:00:00 2001 From: Arun Sharma Date: Fri, 20 Apr 2012 15:41:35 -0700 Subject: perf/x86: Check if user fp is valid Signed-off-by: Arun Sharma Cc: Linus Torvalds Cc: linux-kernel@vger.kernel.org Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1334961696-19580-4-git-send-email-asharma@fb.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'arch/x86/kernel/cpu/perf_event.c') diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index e78bc256aea..c4706cf9c01 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -1757,6 +1757,12 @@ perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs) dump_trace(NULL, regs, NULL, 0, &backtrace_ops, entry); } +static inline int +valid_user_frame(const void __user *fp, unsigned long size) +{ + return (__range_not_ok(fp, size, TASK_SIZE) == 0); +} + #ifdef CONFIG_COMPAT #include @@ -1781,6 +1787,9 @@ perf_callchain_user32(struct pt_regs *regs, struct perf_callchain_entry *entry) if (bytes != sizeof(frame)) break; + if (!valid_user_frame(fp, sizeof(frame))) + break; + perf_callchain_store(entry, frame.return_address); fp = compat_ptr(frame.next_frame); } @@ -1824,6 +1833,9 @@ perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs) if (bytes != sizeof(frame)) break; + if (!valid_user_frame(fp, sizeof(frame))) + break; + perf_callchain_store(entry, frame.return_address); fp = frame.next_frame; } -- cgit v1.2.2