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* perf/ring-buffer: Clarify the use of page::private for high-order AUX ↵Alexander Shishkin2015-08-121-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | allocations A question [1] was raised about the use of page::private in AUX buffer allocations, so let's add a clarification about its intended use. The private field and flag are used by perf's rb_alloc_aux() path to tell the pmu driver the size of each high-order allocation, so that the driver can program those appropriately into its hardware. This only matters for PMUs that don't support hardware scatter tables. Otherwise, every page in the buffer is just a page. This patch adds a comment about the private field to the AUX buffer allocation path. [1] http://marc.info/?l=linux-kernel&m=143803696607968 Reported-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1438063204-665-1-git-send-email-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge branch 'perf/urgent' into perf/core, to pick up fixes before applying ↵Ingo Molnar2015-08-122-26/+71
|\ | | | | | | | | | | new changes Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * perf: Fix PERF_EVENT_IOC_PERIOD migration racePeter Zijlstra2015-08-121-20/+55
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I ran the perf fuzzer, which triggered some WARN()s which are due to trying to stop/restart an event on the wrong CPU. Use the normal IPI pattern to ensure we run the code on the correct CPU. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: bad7192b842c ("perf: Fix PERF_EVENT_IOC_PERIOD to force-reset the period") Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * perf: Fix double-free of the AUX bufferBen Hutchings2015-08-121-4/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If rb->aux_refcount is decremented to zero before rb->refcount, __rb_free_aux() may be called twice resulting in a double free of rb->aux_pages. Fix this by adding a check to __rb_free_aux(). Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Fixes: 57ffc5ca679f ("perf: Fix AUX buffer refcounting") Link: http://lkml.kernel.org/r/1437953468.12842.17.camel@decadent.org.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * perf: Fix fasync handling on inherited eventsPeter Zijlstra2015-08-041-2/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Vince reported that the fasync signal stuff doesn't work proper for inherited events. So fix that. Installing fasync allocates memory and sets filp->f_flags |= FASYNC, which upon the demise of the file descriptor ensures the allocation is freed and state is updated. Now for perf, we can have the events stick around for a while after the original FD is dead because of references from child events. So we cannot copy the fasync pointer around. We can however consistently use the parent's fasync, as that will be updated. Reported-and-Tested-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <stable@vger.kernel.org> Cc: Arnaldo Carvalho deMelo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: eranian@google.com Link: http://lkml.kernel.org/r/1434011521.1495.71.camel@twins Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | tracing, perf: Implement BPF programs attached to uprobesWang Nan2015-08-063-3/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | By copying BPF related operation to uprobe processing path, this patch allow users attach BPF programs to uprobes like what they are already doing on kprobes. After this patch, users are allowed to use PERF_EVENT_IOC_SET_BPF on a uprobe perf event. Which make it possible to profile user space programs and kernel events together using BPF. Because of this patch, CONFIG_BPF_EVENTS should be selected by CONFIG_UPROBE_EVENT to ensure trace_call_bpf() is compiled even if KPROBE_EVENT is not set. Signed-off-by: Wang Nan <wangnan0@huawei.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David Ahern <dsahern@gmail.com> Cc: He Kuang <hekuang@huawei.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kaixu Xia <xiakaixu@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1435716878-189507-3-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* | perf/x86/intel/pt: Do not force sync packets on every schedule-inAlexander Shishkin2015-08-041-2/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, the PT driver zeroes out the status register every time before starting the event. However, all the writable bits are already taken care of in pt_handle_status() function, except the new PacketByteCnt field, which in new versions of PT contains the number of packet bytes written since the last sync (PSB) packet. Zeroing it out before enabling PT forces a sync packet to be written. This means that, with the existing code, a sync packet (PSB and PSBEND, 18 bytes in total) will be generated every time a PT event is scheduled in. To avoid these unnecessary syncs and save a WRMSR in the fast path, this patch changes the default behavior to not clear PacketByteCnt field, so that the sync packets will be generated with the period specified as "psb_period" attribute config field. This has little impact on the trace data as the other packets that are normally sent within PSB+ (between PSB and PSBEND) have their own generation scenarios which do not depend on the sync packets. One exception where we do need to force PSB like this when tracing starts, so that the decoder has a clear sync point in the trace. For this purpose we aready have hw::itrace_started flag, which we are currently using to output PERF_RECORD_ITRACE_START. This patch moves setting itrace_started from perf core to the pmu::start, where it should still be 0 on the very first run. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: acme@infradead.org Cc: adrian.hunter@intel.com Cc: hpa@zytor.com Link: http://lkml.kernel.org/r/1438264104-16189-1-git-send-email-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | perf/x86/hw_breakpoints: Disallow kernel breakpoints unless kprobe-safeAndy Lutomirski2015-08-041-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Code on the kprobe blacklist doesn't want unexpected int3 exceptions. It probably doesn't want unexpected debug exceptions either. Be safe: disallow breakpoints in nokprobes code. On non-CONFIG_KPROBES kernels, there is no kprobe blacklist. In that case, disallow kernel breakpoints entirely. It will be particularly important to keep hw breakpoints out of the entry and NMI code once we move debug exceptions off the IST stack. 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/e14b152af99640448d895e3c2a8c2d5ee19a1325.1438312874.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | uprobes: Fix the waitqueue_active() check in xol_free_insn_slot()Oleg Nesterov2015-07-311-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The xol_free_insn_slot()->waitqueue_active() check is buggy. We need mb() after we set the conditon for wait_event(), or xol_take_insn_slot() can miss the wakeup. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Pratyush Anand <panand@redhat.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150721134036.GA4799@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | uprobes: Use vm_special_mapping to name the XOL vmaOleg Nesterov2015-07-311-10/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Change xol_add_vma() to use _install_special_mapping(), this way we can name the vma installed by uprobes. Currently it looks like private anonymous mapping, this is confusing and complicates the debugging. With this change /proc/$pid/maps reports "[uprobes]". As a side effect this will cause core dumps to include the XOL vma and I think this is good; this can help to debug the problem if the app crashed because it was probed. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Pratyush Anand <panand@redhat.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150721134033.GA4796@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | uprobes: Fix the usage of install_special_mapping()Oleg Nesterov2015-07-311-8/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | install_special_mapping(pages) expects that "pages" is the zero- terminated array while xol_add_vma() passes &area->page, this means that special_mapping_fault() can wrongly use the next member in xol_area (vaddr) as "struct page *". Fortunately, this area is not expandable so pgoff != 0 isn't possible (modulo bugs in special_mapping_vmops), but still this does not look good. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Pratyush Anand <panand@redhat.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150721134031.GA4789@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | uprobes/x86: Make arch_uretprobe_is_alive(RP_CHECK_CALL) more cleverOleg Nesterov2015-07-311-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The previous change documents that cleanup_return_instances() can't always detect the dead frames, the stack can grow. But there is one special case which imho worth fixing: arch_uretprobe_is_alive() can return true when the stack didn't actually grow, but the next "call" insn uses the already invalidated frame. Test-case: #include <stdio.h> #include <setjmp.h> jmp_buf jmp; int nr = 1024; void func_2(void) { if (--nr == 0) return; longjmp(jmp, 1); } void func_1(void) { setjmp(jmp); func_2(); } int main(void) { func_1(); return 0; } If you ret-probe func_1() and func_2() prepare_uretprobe() hits the MAX_URETPROBE_DEPTH limit and "return" from func_2() is not reported. When we know that the new call is not chained, we can do the more strict check. In this case "sp" points to the new ret-addr, so every frame which uses the same "sp" must be dead. The only complication is that arch_uretprobe_is_alive() needs to know was it chained or not, so we add the new RP_CHECK_CHAIN_CALL enum and change prepare_uretprobe() to pass RP_CHECK_CALL only if !chained. Note: arch_uretprobe_is_alive() could also re-read *sp and check if this word is still trampoline_vaddr. This could obviously improve the logic, but I would like to avoid another copy_from_user() especially in the case when we can't avoid the false "alive == T" positives. Tested-by: Pratyush Anand <panand@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Anton Arapov <arapov@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150721134028.GA4786@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | uprobes: Add the "enum rp_check ctx" arg to arch_uretprobe_is_alive()Oleg Nesterov2015-07-311-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | arch/x86 doesn't care (so far), but as Pratyush Anand pointed out other architectures might want why arch_uretprobe_is_alive() was called and use different checks depending on the context. Add the new argument to distinguish 2 callers. Tested-by: Pratyush Anand <panand@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Anton Arapov <arapov@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150721134026.GA4779@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | uprobes: Change prepare_uretprobe() to (try to) flush the dead framesOleg Nesterov2015-07-311-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Change prepare_uretprobe() to flush the !arch_uretprobe_is_alive() return_instance's. This is not needed correctness-wise, but can help to avoid the failure caused by MAX_URETPROBE_DEPTH. Note: in this case arch_uretprobe_is_alive() can be false positive, the stack can grow after longjmp(). Unfortunately, the kernel can't 100% solve this problem, but see the next patch. Tested-by: Pratyush Anand <panand@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Anton Arapov <arapov@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150721134023.GA4776@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | uprobes: Change handle_trampoline() to flush the frames invalidated by longjmp()Oleg Nesterov2015-07-311-11/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Test-case: #include <stdio.h> #include <setjmp.h> jmp_buf jmp; void func_2(void) { longjmp(jmp, 1); } void func_1(void) { if (setjmp(jmp)) return; func_2(); printf("ERR!! I am running on the caller's stack\n"); } int main(void) { func_1(); return 0; } fails if you probe func_1() and func_2() because handle_trampoline() assumes that the probed function should must return and hit the bp installed be prepare_uretprobe(). But in this case func_2() does not return, so when func_1() returns the kernel uses the no longer valid return_instance of func_2(). Change handle_trampoline() to unwind ->return_instances until we know that the next chain is alive or NULL, this ensures that the current chain is the last we need to report and free. Alternatively, every return_instance could use unique trampoline_vaddr, in this case we could use it as a key. And this could solve the problem with sigaltstack() automatically. But this approach needs more changes, and it puts the "hard" limit on MAX_URETPROBE_DEPTH. Plus it can not solve another problem partially fixed by the next patch. Note: this change has no effect on !x86, the arch-agnostic version of arch_uretprobe_is_alive() just returns "true". TODO: as documented by the previous change, arch_uretprobe_is_alive() can be fooled by sigaltstack/etc. Tested-by: Pratyush Anand <panand@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Anton Arapov <arapov@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150721134021.GA4773@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | uprobes/x86: Reimplement arch_uretprobe_is_alive()Oleg Nesterov2015-07-311-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add the x86 specific version of arch_uretprobe_is_alive() helper. It returns true if the stack frame mangled by prepare_uretprobe() is still on stack. So if it returns false, we know that the probed function has already returned. We add the new return_instance->stack member and change the generic code to initialize it in prepare_uretprobe, but it should be equally useful for other architectures. TODO: this assumes that the probed application can't use multiple stacks (say sigaltstack). We will try to improve this logic later. Tested-by: Pratyush Anand <panand@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Anton Arapov <arapov@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150721134018.GA4766@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | uprobes: Export 'struct return_instance', introduce arch_uretprobe_is_alive()Oleg Nesterov2015-07-311-9/+5Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add the new "weak" helper, arch_uretprobe_is_alive(), used by the next patches. It should return true if this return_instance is still valid. The arch agnostic version just always returns true. The patch exports "struct return_instance" for the architectures which want to override this hook. We can also cleanup prepare_uretprobe() if we pass the new return_instance to arch_uretprobe_hijack_return_addr(). Tested-by: Pratyush Anand <panand@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Anton Arapov <arapov@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150721134016.GA4762@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | uprobes: Change handle_trampoline() to find the next chain beforehandOleg Nesterov2015-07-311-11/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | No functional changes, preparation. Add the new helper, find_next_ret_chain(), which finds the first !chained entry and returns its ->next. Yes, it is suboptimal. We probably want to turn ->chained into ->start_of_this_chain pointer and avoid another loop. But this needs the boring changes in dup_utask(), so lets do this later. Change the main loop in handle_trampoline() to unwind the stack until ri is equal to the pointer returned by this new helper. Tested-by: Pratyush Anand <panand@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Anton Arapov <arapov@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150721134013.GA4755@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | uprobes: Change prepare_uretprobe() to use uprobe_warn()Oleg Nesterov2015-07-311-7/+3Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Turn the last pr_warn() in uprobes.c into uprobe_warn(). While at it: - s/kzalloc/kmalloc, we initialize every member of 'ri' - remove the pointless comment above the obvious code Tested-by: Pratyush Anand <panand@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Anton Arapov <arapov@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150721134010.GA4752@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | uprobes: Send SIGILL if handle_trampoline() failsOleg Nesterov2015-07-311-11/+10Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 1. It doesn't make sense to continue if handle_trampoline() fails, change handle_swbp() to always return after this call. 2. Turn pr_warn() into uprobe_warn(), and change handle_trampoline() to send SIGILL on failure. It is pointless to return to user mode with the corrupted instruction_pointer() which we can't restore. Tested-by: Pratyush Anand <panand@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Anton Arapov <arapov@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150721134008.GA4745@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | uprobes: Introduce free_ret_instance()Oleg Nesterov2015-07-311-14/+13Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We can simplify uprobe_free_utask() and handle_uretprobe_chain() if we add a simple helper which does put_uprobe/kfree and returns the ->next return_instance. Tested-by: Pratyush Anand <panand@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Anton Arapov <arapov@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150721134006.GA4740@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | uprobes: Introduce get_uprobe()Oleg Nesterov2015-07-311-19/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Cosmetic. Add the new trivial helper, get_uprobe(). It matches put_uprobe() we already have and we can simplify a couple of its users. Tested-by: Pratyush Anand <panand@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Anton Arapov <arapov@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150721134003.GA4736@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | Merge branch 'perf/urgent' into perf/core, to merge fixes before pulling ↵Ingo Molnar2015-07-313-23/+39
|\| | | | | | | | | | | more changes Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * perf: Fix running time accountingPeter Zijlstra2015-07-271-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A recent fix to the shadow timestamp inadvertly broke the running time accounting. We must not update the running timestamp if we fail to schedule the event, the event will not have ran. This can (and did) result in negative total runtime because the stopped timestamp was before the running timestamp (we 'started' but never stopped the event -- because it never really started we didn't have to stop it either). Reported-and-Tested-by: Vince Weaver <vincent.weaver@maine.edu> Fixes: 72f669c0086f ("perf: Update shadow timestamp before add event") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: stable@vger.kernel.org # 4.1 Cc: Shaohua Li <shli@fb.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds2015-07-261-3/+3
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Thomas Gleixner: "This update contains: - the manual revert of the SYSCALL32 changes which caused a regression - a fix for the MPX vma handling - three fixes for the ioremap 'is ram' checks. - PAT warning fixes - a trivial fix for the size calculation of TLB tracepoints - handle old EFI structures gracefully This also contains a PAT fix from Jan plus a revert thereof. Toshi explained why the code is correct" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm/pat: Revert 'Adjust default caching mode translation tables' x86/asm/entry/32: Revert 'Do not use R9 in SYSCALL32' commit x86/mm: Fix newly introduced printk format warnings mm: Fix bugs in region_is_ram() x86/mm: Remove region_is_ram() call from ioremap x86/mm: Move warning from __ioremap_check_ram() to the call site x86/mm/pat, drivers/media/ivtv: Move the PAT warning and replace WARN() with pr_warn() x86/mm/pat, drivers/infiniband/ipath: Replace WARN() with pr_warn() x86/mm/pat: Adjust default caching mode translation tables x86/fpu: Disable dependent CPU features on "noxsave" x86/mpx: Do not set ->vm_ops on MPX VMAs x86/mm: Add parenthesis for TLB tracepoint size calculation efi: Handle memory error structures produced based on old versions of standard
| | * mm: Fix bugs in region_is_ram()Toshi Kani2015-07-221-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | region_is_ram() looks up the iomem_resource table to check if a target range is in RAM. However, it always returns with -1 due to invalid range checks. It always breaks the loop at the first entry of the table. Another issue is that it compares p->flags and flags, but it always fails. flags is declared as int, which makes it as a negative value with IORESOURCE_BUSY (0x80000000) set while p->flags is unsigned long. Fix the range check and flags so that region_is_ram() works as advertised. Signed-off-by: Toshi Kani <toshi.kani@hp.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Cc: Mike Travis <travis@sgi.com> Cc: Luis R. Rodriguez <mcgrof@suse.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Roland Dreier <roland@purestorage.com> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/1437088996-28511-4-git-send-email-toshi.kani@hp.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | Merge tag 'trace-v4.2-rc2-fix3' of ↵Linus Torvalds2015-07-251-18/+34
| |\ \ | | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull ftrace fix from Steven Rostedt: "Back in 3.16 the ftrace code was redesigned and cleaned up to remove the double iteration list (one for registered ftrace ops, and one for registered "global" ops), to just use one list. That simplified the code but also broke the function tracing filtering on pid. This updates the code to handle the filtering again with the new logic" * tag 'trace-v4.2-rc2-fix3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: ftrace: Fix breakage of set_ftrace_pid
| | * ftrace: Fix breakage of set_ftrace_pidSteven Rostedt (Red Hat)2015-07-241-18/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 4104d326b670 ("ftrace: Remove global function list and call function directly") simplified the ftrace code by removing the global_ops list with a new design. But this cleanup also broke the filtering of PIDs that are added to the set_ftrace_pid file. Add back the proper hooks to have pid filtering working once again. Cc: stable@vger.kernel.org # 3.16+ Reported-by: Matt Fleming <matt@console-pimps.org> Reported-by: Richard Weinberger <richard.weinberger@gmail.com> Tested-by: Matt Fleming <matt@console-pimps.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | | perf: Add PERF_RECORD_SWITCH to indicate context switchesAdrian Hunter2015-07-241-0/+103
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are already two events for context switches, namely the tracepoint sched:sched_switch and the software event context_switches. Unfortunately neither are suitable for use by non-privileged users for the purpose of synchronizing hardware trace data (e.g. Intel PT) to the context switch. Tracepoints are no good at all for non-privileged users because they need either CAP_SYS_ADMIN or /proc/sys/kernel/perf_event_paranoid <= -1. On the other hand, kernel software events need either CAP_SYS_ADMIN or /proc/sys/kernel/perf_event_paranoid <= 1. Now many distributions do default perf_event_paranoid to 1 making context_switches a contender, except it has another problem (which is also shared with sched:sched_switch) which is that it happens before perf schedules events out instead of after perf schedules events in. Whereas a privileged user can see all the events anyway, a non-privileged user only sees events for their own processes, in other words they see when their process was scheduled out not when it was scheduled in. That presents two problems to use the event: 1. the information comes too late, so tools have to look ahead in the event stream to find out what the current state is 2. if they are unlucky tracing might have stopped before the context-switches event is recorded. This new PERF_RECORD_SWITCH event does not have those problems and it also has a couple of other small advantages. It is easier to use because it is an auxiliary event (like mmap, comm and task events) which can be enabled by setting a single bit. It is smaller than sched:sched_switch and easier to parse. To make the event useful for privileged users also, if the context is cpu-wide then the event record will be PERF_RECORD_SWITCH_CPU_WIDE which is the same as PERF_RECORD_SWITCH except it also provides the next or previous pid/tid. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Jiri Olsa <jolsa@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Pawel Moll <pawel.moll@arm.com> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/1437471846-26995-2-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* | Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds2015-07-181-1/+6
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Ingo Molnar: "Two families of fixes: - Fix an FPU context related boot crash on newer x86 hardware with larger context sizes than what most people test. To fix this without ugly kludges or extensive reverts we had to touch core task allocator, to allow x86 to determine the task size dynamically, at boot time. I've tested it on a number of x86 platforms, and I cross-built it to a handful of architectures: (warns) (warns) testing x86-64: -git: pass ( 0), -tip: pass ( 0) testing x86-32: -git: pass ( 0), -tip: pass ( 0) testing arm: -git: pass ( 1359), -tip: pass ( 1359) testing cris: -git: pass ( 1031), -tip: pass ( 1031) testing m32r: -git: pass ( 1135), -tip: pass ( 1135) testing m68k: -git: pass ( 1471), -tip: pass ( 1471) testing mips: -git: pass ( 1162), -tip: pass ( 1162) testing mn10300: -git: pass ( 1058), -tip: pass ( 1058) testing parisc: -git: pass ( 1846), -tip: pass ( 1846) testing sparc: -git: pass ( 1185), -tip: pass ( 1185) ... so I hope the cross-arch impact 'none', as intended. (by Dave Hansen) - Fix various NMI handling related bugs unearthed by the big asm code rewrite and generally make the NMI code more robust and more maintainable while at it. These changes are a bit late in the cycle, I hope they are still acceptable. (by Andy Lutomirski)" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/fpu, sched: Introduce CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT and use it on x86 x86/fpu, sched: Dynamically allocate 'struct fpu' x86/entry/64, x86/nmi/64: Add CONFIG_DEBUG_ENTRY NMI testing code x86/nmi/64: Make the "NMI executing" variable more consistent x86/nmi/64: Minor asm simplification x86/nmi/64: Use DF to avoid userspace RSP confusing nested NMI detection x86/nmi/64: Reorder nested NMI checks x86/nmi/64: Improve nested NMI comments x86/nmi/64: Switch stacks on userspace NMI entry x86/nmi/64: Remove asm code that saves CR2 x86/nmi: Enable nested do_nmi() handling for 64-bit kernels
| * | x86/fpu, sched: Introduce CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT and use it ↵Ingo Molnar2015-07-181-6/+5Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | on x86 Don't burden architectures without dynamic task_struct sizing with the overhead of dynamic sizing. Also optimize the x86 code a bit by caching task_struct_size. Acked-and-Tested-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave@sr71.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1437128892-9831-3-git-send-email-mingo@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | x86/fpu, sched: Dynamically allocate 'struct fpu'Dave Hansen2015-07-181-1/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The FPU rewrite removed the dynamic allocations of 'struct fpu'. But, this potentially wastes massive amounts of memory (2k per task on systems that do not have AVX-512 for instance). Instead of having a separate slab, this patch just appends the space that we need to the 'task_struct' which we dynamically allocate already. This saves from doing an extra slab allocation at fork(). The only real downside here is that we have to stick everything and the end of the task_struct. But, I think the BUILD_BUG_ON()s I stuck in there should keep that from being too fragile. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave@sr71.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1437128892-9831-2-git-send-email-mingo@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | Merge branch 'timers-urgent-for-linus' of ↵Linus Torvalds2015-07-182-1/+1
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fix from Ingo Molnar: "Fix for a misplaced export that can cause build failures in certain (rare) Kconfig situations" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tick: Move the export of tick_broadcast_oneshot_control to the proper place
| * | | tick: Move the export of tick_broadcast_oneshot_control to the proper placeThomas Gleixner2015-07-142-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | tick_broadcast_oneshot_control got moved from tick-broadcast to tick-common, but the export stayed in the old place. Fix it up. Fixes: f32dd1170511 'tick/broadcast: Make idle check independent from mode and config' Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | | Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds2015-07-181-1/+1
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fix from Ingo Molnar: "A oneliner rq throttling fix" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/fair: Test list head instead of list entry in throttle_cfs_rq()
| * | | | sched/fair: Test list head instead of list entry in throttle_cfs_rq()Cong Wang2015-07-061-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | According to the comments, we need to test if this is the first throttled task, however, list_empty() tests on the entry cfs_rq->throttled_list, not the head, this is wrong. This is a bug because we don't re-init the list entry after removing it from the list, so list_empty() could return false even if the list is really empty. Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Cong Wang <cwang@twopensource.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Ben Segall <bsegall@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1435174907-432-1-git-send-email-xiyou.wangcong@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | | Merge branch 'irq-urgent-for-linus' of ↵Linus Torvalds2015-07-182-14/+13Star
|\ \ \ \ \ | |_|_|/ / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull irq fixes from Ingo Molnar: "Misc irq fixes: - two driver fixes - a Xen regression fix - a nested irq thread crash fix" * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: irqchip/gicv3-its: Fix mapping of LPIs to collections genirq: Prevent resend to interrupts marked IRQ_NESTED_THREAD genirq: Revert sparse irq locking around __cpu_up() and move it to x86 for now gpio/davinci: Fix race in installing chained irq handler
| * | | | genirq: Prevent resend to interrupts marked IRQ_NESTED_THREADThomas Gleixner2015-07-171-5/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The resend mechanism happily calls the interrupt handler of interrupts which are marked IRQ_NESTED_THREAD from softirq context. This can result in crashes because the interrupt handler is not the proper way to invoke the device handlers. They must be invoked via handle_nested_irq. Prevent the resend even if the interrupt has no valid parent irq set. Its better to have a lost interrupt than a crashing machine. Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org
| * | | | genirq: Revert sparse irq locking around __cpu_up() and move it to x86 for nowThomas Gleixner2015-07-151-9/+0Star
| | |/ / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Boris reported that the sparse_irq protection around __cpu_up() in the generic code causes a regression on Xen. Xen allocates interrupts and some more in the xen_cpu_up() function, so it deadlocks on the sparse_irq_lock. There is no simple fix for this and we really should have the protection for all architectures, but for now the only solution is to move it to x86 where actual wreckage due to the lack of protection has been observed. Reported-and-tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Fixes: a89941816726 'hotplug: Prevent alloc/free of irq descriptors during cpu up/down' Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: xiao jin <jin.xiao@intel.com> Cc: Joerg Roedel <jroedel@suse.de> Cc: Borislav Petkov <bp@suse.de> Cc: Yanmin Zhang <yanmin_zhang@linux.intel.com> Cc: xen-devel <xen-devel@lists.xenproject.org>
* | | | Merge tag 'trace-v4.2-rc1-fix' of ↵Linus Torvalds2015-07-152-7/+11
|\ \ \ \ | |/ / / |/| | / | | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fix from Steven Rostedt: "Fengguang Wu discovered a crash that happened to be because of the branch tracer (traces unlikely and likely branches) when enabled with certain debug options. What happened was that various debug options like lockdep and DEBUG_PREEMPT can cause parts of the branch tracer to recurse outside its recursion protection. In fact, part of its recursion protection used these features that caused the lockup. This cleans up the code a little and makes the recursion protection a bit more robust" * tag 'trace-v4.2-rc1-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Have branch tracer use recursive field of task struct
| * | tracing: Have branch tracer use recursive field of task structSteven Rostedt (Red Hat)2015-07-082-7/+11
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fengguang Wu's tests triggered a bug in the branch tracer's start up test when CONFIG_DEBUG_PREEMPT set. This was because that config adds some debug logic in the per cpu field, which calls back into the branch tracer. The branch tracer has its own recursive checks, but uses a per cpu variable to implement it. If retrieving the per cpu variable calls back into the branch tracer, you can see how things will break. Instead of using a per cpu variable, use the trace_recursion field of the current task struct. Simply set a bit when entering the branch tracing and clear it when leaving. If the bit is set on entry, just don't do the tracing. There's also the case with lockdep, as the local_irq_save() called before the recursion can also trigger code that can call back into the function. Changing that to a raw_local_irq_save() will protect that as well. This prevents the recursion and the inevitable crash that follows. Link: http://lkml.kernel.org/r/20150630141803.GA28071@wfg-t540p.sh.intel.com Cc: stable@vger.kernel.org # 3.10+ Reported-by: Fengguang Wu <fengguang.wu@intel.com> Tested-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | Merge branch 'timers-urgent-for-linus' of ↵Linus Torvalds2015-07-124-70/+148
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fixes from Thomas Gleixner: "This update from the timer departement contains: - A series of patches which address a shortcoming in the tick broadcast code. If the broadcast device is not available or an hrtimer emulated broadcast device, some of the original assumptions lead to boot failures. I rather plugged all of the corner cases instead of only addressing the issue reported, so the change got a little larger. Has been extensivly tested on x86 and arm. - Get rid of the last holdouts using do_posix_clock_monotonic_gettime() - A regression fix for the imx clocksource driver - An update to the new state callbacks mechanism for clockevents. This is required to simplify the conversion, which will take place in 4.3" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tick/broadcast: Prevent NULL pointer dereference time: Get rid of do_posix_clock_monotonic_gettime cris: Replace do_posix_clock_monotonic_gettime() tick/broadcast: Unbreak CONFIG_GENERIC_CLOCKEVENTS=n build tick/broadcast: Handle spurious interrupts gracefully tick/broadcast: Check for hrtimer broadcast active early tick/broadcast: Return busy when IPI is pending tick/broadcast: Return busy if periodic mode and hrtimer broadcast tick/broadcast: Move the check for periodic mode inside state handling tick/broadcast: Prevent deep idle if no broadcast device available tick/broadcast: Make idle check independent from mode and config tick/broadcast: Sanity check the shutdown of the local clock_event tick/broadcast: Prevent hrtimer recursion clockevents: Allow set-state callbacks to be optional clocksource/imx: Define clocksource for mx27
| * | tick/broadcast: Prevent NULL pointer dereferenceThomas Gleixner2015-07-111-8/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Dan reported that the recent changes to the broadcast code introduced a potential NULL dereference. Add the proper check. Fixes: e0454311903d "tick/broadcast: Sanity check the shutdown of the local clock_event" Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | tick/broadcast: Handle spurious interrupts gracefullyThomas Gleixner2015-07-071-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Andriy reported that on a virtual machine the warning about negative expiry time in the clock events programming code triggered: hpet: hpet0 irq 40 for MSI hpet: hpet1 irq 41 for MSI Switching to clocksource hpet WARNING: at kernel/time/clockevents.c:239 [<ffffffff810ce6eb>] clockevents_program_event+0xdb/0xf0 [<ffffffff810cf211>] tick_handle_periodic_broadcast+0x41/0x50 [<ffffffff81016525>] timer_interrupt+0x15/0x20 When the second hpet is installed as a per cpu timer the broadcast event is not longer required and stopped, which sets the next_evt of the broadcast device to KTIME_MAX. If after that a spurious interrupt happens on the broadcast device, then the current code blindly handles it and tries to reprogram the broadcast device afterwards, which adds the period to next_evt. KTIME_MAX + period results in a negative expiry value causing the WARN_ON in the clockevents code to trigger. Add a proper check for the state of the broadcast device into the interrupt handler and return if the interrupt is spurious. [ Folded in pointer fix from Sudeep ] Reported-by: Andriy Gapon <avg@FreeBSD.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/20150705205221.802094647@linutronix.de
| * | tick/broadcast: Check for hrtimer broadcast active earlyThomas Gleixner2015-07-071-10/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the current cpu is the one which has the hrtimer based broadcast queued then we better return busy immediately instead of going through loops and hoops to figure that out. [ Split out from a larger combo patch ] Tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
| * | tick/broadcast: Return busy when IPI is pendingThomas Gleixner2015-07-071-3/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Tell the idle code not to go deep if the broadcast IPI is about to arrive. [ Split out from a larger combo patch ] Tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
| * | tick/broadcast: Return busy if periodic mode and hrtimer broadcastThomas Gleixner2015-07-071-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the system is in periodic mode and the broadcast device is hrtimer based, return busy as we have no proper handling for this. [ Split out from a larger combo patch ] Tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
| * | tick/broadcast: Move the check for periodic mode inside state handlingThomas Gleixner2015-07-071-14/+8Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We need to check more than the periodic mode for proper operation in all runtime combinations. To avoid code duplication move the check into the enter state handling. No functional change. [ Split out from a larger combo patch ] Reported-and-tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
| * | tick/broadcast: Prevent deep idle if no broadcast device availableThomas Gleixner2015-07-071-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a check for a installed broadcast device to the oneshot control function and return busy if not. [ Split out from a larger combo patch ] Reported-and-tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
| * | tick/broadcast: Make idle check independent from mode and configThomas Gleixner2015-07-073-15/+42
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently the broadcast busy check, which prevents the idle code from going into deep idle, works only in one shot mode. If NOHZ and HIGHRES are off (config or command line) there is no sanity check at all, so under certain conditions cpus are allowed to go into deep idle, where the local timer stops, and are not woken up again because there is no broadcast timer installed or a hrtimer based broadcast device is not evaluated. Move tick_broadcast_oneshot_control() into the common code and provide proper subfunctions for the various config combinations. The common check in tick_broadcast_oneshot_control() is for the C3STOP misfeature flag of the local clock event device. If its not set, idle can proceed. If set, further checks are necessary. Provide checks for the trivial cases: - If broadcast is disabled in the config, then return busy - If oneshot mode (NOHZ/HIGHES) is disabled in the config, return busy if the broadcast device is hrtimer based. - If oneshot mode is enabled in the config call the original tick_broadcast_oneshot_control() function. That function needs extra checks which will be implemented in seperate patches. [ Split out from a larger combo patch ] Reported-and-tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
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