summaryrefslogtreecommitdiff
path: root/kernel
AgeCommit message (Collapse)Author
2016-05-03Merge tag 'trace-fixes-v4.6-rc6' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fix from Steven Rostedt: "Chunyu Hu noticed that if one writes into the trigger files within the ftrace subsystem of events that it can cause an oops. This file is only writable by root, but still is a bug that needs to be fixed" * tag 'trace-fixes-v4.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Don't display trigger file for events that can't be enabled
2016-05-03tracing: Use temp buffer when filtering eventsSteven Rostedt (Red Hat)
Filtering of events requires the data to be written to the ring buffer before it can be decided to filter or not. This is because the parameters of the filter are based on the result that is written to the ring buffer and not on the parameters that are passed into the trace functions. The ftrace ring buffer is optimized for writing into the ring buffer and committing. The discard procedure used when filtering decides the event should be discarded is much more heavy weight. Thus, using a temporary filter when filtering events can speed things up drastically. Without a temp buffer we have: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.790706626 seconds time elapsed ( +- 0.71% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.566904059 seconds time elapsed ( +- 0.27% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.690598511 seconds time elapsed ( +- 0.19% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.707486364 seconds time elapsed ( +- 0.30% ) The first run above is without any tracing, just to get a based figure. hackbench takes ~0.79 seconds to run on the system. The second run enables tracing all events where nothing is filtered. This increases the time by 100% and hackbench takes 1.57 seconds to run. The third run filters all events where the preempt count will equal "20" (this should never happen) thus all events are discarded. This takes 1.69 seconds to run. This is 10% slower than just committing the events! The last run enables all events and filters where the filter will commit all events, and this takes 1.70 seconds to run. The filtering overhead is approximately 10%. Thus, the discard and commit of an event from the ring buffer may be about the same time. With this patch, the numbers change: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.778233033 seconds time elapsed ( +- 0.38% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.582102692 seconds time elapsed ( +- 0.28% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.309230710 seconds time elapsed ( +- 0.22% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.786001924 seconds time elapsed ( +- 0.20% ) The first run is again the base with no tracing. The second run is all tracing with no filtering. It is a little slower, but that may be well within the noise. The third run shows that discarding all events only took 1.3 seconds. This is a speed up of 23%! The discard is much faster than even the commit. The one downside is shown in the last run. Events that are not discarded by the filter will take longer to add, this is due to the extra copy of the event. Cc: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-05-03tracing: Don't display trigger file for events that can't be enabledChunyu Hu
Currently register functions for events will be called through the 'reg' field of event class directly without any check when seting up triggers. Triggers for events that don't support register through debug fs (events under events/ftrace are for trace-cmd to read event format, and most of them don't have a register function except events/ftrace/functionx) can't be enabled at all, and an oops will be hit when setting up trigger for those events, so just not creating them is an easy way to avoid the oops. Link: http://lkml.kernel.org/r/1462275274-3911-1-git-send-email-chuhu@redhat.com Cc: stable@vger.kernel.org # 3.14+ Fixes: 85f2b08268c01 ("tracing: Add basic event trigger framework") Signed-off-by: Chunyu Hu <chuhu@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-05-03signals/sigaltstack: Implement SS_AUTODISARM flagStas Sergeev
This patch implements the SS_AUTODISARM flag that can be OR-ed with SS_ONSTACK when forming ss_flags. When this flag is set, sigaltstack will be disabled when entering the signal handler; more precisely, after saving sas to uc_stack. When leaving the signal handler, the sigaltstack is restored by uc_stack. When this flag is used, it is safe to switch from sighandler with swapcontext(). Without this flag, the subsequent signal will corrupt the state of the switched-away sighandler. To detect the support of this functionality, one can do: err = sigaltstack(SS_DISABLE | SS_AUTODISARM); if (err && errno == EINVAL) unsupported(); Signed-off-by: Stas Sergeev <stsp@list.ru> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Aleksa Sarai <cyphar@cyphar.com> Cc: Amanieu d'Antras <amanieu@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Heinrich Schuchardt <xypron.glpk@gmx.de> Cc: Jason Low <jason.low2@hp.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Moore <pmoore@redhat.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Richard Weinberger <richard@nod.at> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Shuah Khan <shuahkh@osg.samsung.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: linux-api@vger.kernel.org Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/1460665206-13646-4-git-send-email-stsp@list.ru Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-03signals/sigaltstack: Prepare to add new SS_xxx flagsStas Sergeev
This patch adds SS_FLAG_BITS - the mask that splits sigaltstack mode values and bit-flags. Since there is no bit-flags yet, the mask is defined to 0. The flags are added by subsequent patches. With every new flag, the mask should have the appropriate bit cleared. This makes sure if some flag is tried on a kernel that doesn't support it, the -EINVAL error will be returned, because such a flag will be treated as an invalid mode rather than the bit-flag. That way the existence of the particular features can be probed at run-time. This change was suggested by Andy Lutomirski: https://lkml.org/lkml/2016/3/6/158 Signed-off-by: Stas Sergeev <stsp@list.ru> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Amanieu d'Antras <amanieu@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Richard Weinberger <richard@nod.at> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Shuah Khan <shuahkh@osg.samsung.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: linux-api@vger.kernel.org Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/1460665206-13646-3-git-send-email-stsp@list.ru Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-02tracing: Remove TRACE_EVENT_FL_USE_CALL_FILTER logicSteven Rostedt (Red Hat)
Nothing sets TRACE_EVENT_FL_USE_CALL_FILTER anymore. Remove it. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-05-02Merge getxattr prototype change into work.lookupsAl Viro
The rest of work.xattr stuff isn't needed for this branch
2016-05-02Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds
Pull networking fixes from David Miller: 1) MODULE_FIRMWARE firmware string not correct for iwlwifi 8000 chips, from Sara Sharon. 2) Fix SKB size checks in batman-adv stack on receive, from Sven Eckelmann. 3) Leak fix on mac80211 interface add error paths, from Johannes Berg. 4) Cannot invoke napi_disable() with BH disabled in myri10ge driver, fix from Stanislaw Gruszka. 5) Fix sign extension problem when computing feature masks in net_gso_ok(), from Marcelo Ricardo Leitner. 6) lan78xx driver doesn't count packets and packet lengths in its statistics properly, fix from Woojung Huh. 7) Fix the buffer allocation sizes in pegasus USB driver, from Petko Manolov. 8) Fix refcount overflows in bpf, from Alexei Starovoitov. 9) Unified dst cache handling introduced a preempt warning in ip_tunnel, fix by resetting rather then setting the cached route. From Paolo Abeni. 10) Listener hash collision test fix in soreuseport, from Craig Gallak * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (47 commits) gre: do not pull header in ICMP error processing net: Implement net_dbg_ratelimited() for CONFIG_DYNAMIC_DEBUG case tipc: only process unicast on intended node cxgb3: fix out of bounds read net/smscx5xx: use the device tree for mac address soreuseport: Fix TCP listener hash collision net: l2tp: fix reversed udp6 checksum flags ip_tunnel: fix preempt warning in ip tunnel creation/updating samples/bpf: fix trace_output example bpf: fix check_map_func_compatibility logic bpf: fix refcnt overflow drivers: net: cpsw: use of_phy_connect() in fixed-link case dt: cpsw: phy-handle, phy_id, and fixed-link are mutually exclusive drivers: net: cpsw: don't ignore phy-mode if phy-handle is used drivers: net: cpsw: fix segfault in case of bad phy-handle drivers: net: cpsw: fix parsing of phy-handle DT property in dual_emac config MAINTAINERS: net: Change maintainer for GRETH 10/100/1G Ethernet MAC device driver gre: reject GUE and FOU in collect metadata mode pegasus: fixes reported packet length pegasus: fixes URB buffer allocation size; ...
2016-05-02genirq: Allow the affinity of a percpu interrupt to be set/retrievedMarc Zyngier
In order to prepare the genirq layer for the concept of partitionned percpu interrupts, let's allow an affinity to be associated with such an interrupt. We introduce: - irq_set_percpu_devid_partition: flag an interrupt as a percpu-devid interrupt, and associate it with an affinity - irq_get_percpu_devid_partition: allow the affinity of that interrupt to be retrieved. This will allow a driver to discover which CPUs the per-cpu interrupt can actually fire on. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: devicetree@vger.kernel.org Cc: Jason Cooper <jason@lakedaemon.net> Cc: Will Deacon <will.deacon@arm.com> Cc: Rob Herring <robh+dt@kernel.org> Link: http://lkml.kernel.org/r/1460365075-7316-3-git-send-email-marc.zyngier@arm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-05-02irqdomain: Allow domain matching on irq_fwspecMarc Zyngier
When iterating over the irq domain list, we try to match a domain either by calling a match() function or by comparing a number of fields passed as parameters. Both approaches are a bit restrictive: - match() is DT specific and only takes a device node - the fallback case only deals with the fwnode_handle It would be useful if we had a per-domain function that would actually perform the matching check on the whole of the irq_fwspec structure. This would allow for a domain to triage matching attempts that need to extend beyond the fwnode. Let's introduce irq_find_matching_fwspec(), which takes a full blown irq_fwspec structure, and call into a select() function implemented by the irqdomain. irq_find_matching_fwnode() is made a wrapper around irq_find_matching_fwspec in order to preserve compatibility. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: devicetree@vger.kernel.org Cc: Jason Cooper <jason@lakedaemon.net> Cc: Will Deacon <will.deacon@arm.com> Cc: Rob Herring <robh+dt@kernel.org> Link: http://lkml.kernel.org/r/1460365075-7316-2-git-send-email-marc.zyngier@arm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-05-02genirq: Add error code reporting to irq_{reserve,destroy}_ipiMatt Redfearn
Make these functions return appropriate error codes when something goes wrong. Previously irq_destroy_ipi returned void making it impossible to notify the caller if the request could not be fulfilled. Patch 1 in the series added another condition in which this could fail in addition to the existing ones. irq_reserve_ipi returned an unsigned int meaning it could only return 0 on failure and give the caller no indication as to why the request failed. As time goes on there are likely to be further conditions added in which these functions can fail. These APIs and the IPI IRQ domain are new in 4.6 and the number of existing call sites are low, changing the API now has little impact on the code, while making it easier for these functions to grow over time. Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com> Cc: linux-mips@linux-mips.org Cc: jason@lakedaemon.net Cc: marc.zyngier@arm.com Cc: ralf@linux-mips.org Cc: Qais Yousef <qsyousef@gmail.com> Cc: lisa.parratt@imgtec.com Cc: jiang.liu@linux.intel.com Link: http://lkml.kernel.org/r/1461568464-31701-2-git-send-email-matt.redfearn@imgtec.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-05-02genirq: Make irq_destroy_ipi take a cpumask of IPIs to destroyMatt Redfearn
Previously irq_destroy_ipi() would destroy IPIs to all CPUs that were configured by irq_reserve_ipi(). This change makes it possible to destroy just a subset of the IPIs. This may be useful to remove IPIs to CPUs that have been hot removed so that the IRQ numbers allocated within the IPI domain can be re-used. The original behaviour is restored by passing the complete mask that the IPI was created with. There are currently no users of this function that would break from the API change. Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com> Cc: linux-mips@linux-mips.org Cc: jason@lakedaemon.net Cc: marc.zyngier@arm.com Cc: ralf@linux-mips.org Cc: Qais Yousef <qsyousef@gmail.com> Cc: lisa.parratt@imgtec.com Cc: jiang.liu@linux.intel.com Link: http://lkml.kernel.org/r/1461568464-31701-1-git-send-email-matt.redfearn@imgtec.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-04-29tracing: Remove unused function trace_current_buffer_lock_reserve()Steven Rostedt (Red Hat)
trace_current_buffer_lock_reserve() has no more users. Remove it. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-29tracing: Remove one use of trace_current_buffer_lock_reserve()Steven Rostedt (Red Hat)
The only user of trace_current_buffer_lock_reserve() is in the boot up self tests. Restructure the code a little to have that code use what everything else uses: trace_event_buffer_lock_reserve(). Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-30livepatch: make object/func-walking helpers more robustMiroslav Benes
Current object-walking helper checks the presence of obj->funcs to determine the end of objs array in klp_object structure. This is somewhat fragile because one can easily forget about funcs definition during livepatch creation. In such a case the livepatch module is successfully loaded and all objects after the incorrect one are omitted. This is very confusing. Let's make the helper more robust and check also for the other external member, name. Thus the helper correctly stops on an empty item of the array. We need to have a check for obj->funcs in klp_init_object() to make it work. The same applies to a func-walking helper. As a benefit we'll check for new_func member definition during the livepatch initialization. There is no such check anywhere in the code now. [jkosina@suse.cz: fix shortlog] Signed-off-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Jessica Yu <jeyu@redhat.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2016-04-29tracing: Have trace_buffer_unlock_commit() call the _regs version with NULLSteven Rostedt (Red Hat)
There's no real difference between trace_buffer_unlock_commit() and trace_buffer_unlock_commit_regs() except that the former passes NULL to ftrace_stack_trace() instead of regs. Have the former be a static inline of the latter which passes NULL for regs. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-29tracing: Remove unused function trace_current_buffer_discard_commit()Steven Rostedt (Red Hat)
The function trace_current_buffer_discard_commit() has no callers, remove it. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-29tracing: Move trace_buffer_unlock_commit{_regs}() to local headerSteven Rostedt (Red Hat)
The functions trace_buffer_unlock_commit() and the _regs() version are only used within the kernel/trace directory. Move them to the local header and remove the export as well. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-29tracing: Fold filter_check_discard() into its only userSteven Rostedt (Red Hat)
The function filter_check_discard() is small and only called by one user, its code can be folded into that one caller and make the code a bit less comlplex. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-29Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge fixes from Andrew Morton: "20 fixes" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: Documentation/sysctl/vm.txt: update numa_zonelist_order description lib/stackdepot.c: allow the stack trace hash to be zero rapidio: fix potential NULL pointer dereference mm/memory-failure: fix race with compound page split/merge ocfs2/dlm: return zero if deref_done message is successfully handled Ananth has moved kcov: don't profile branches in kcov kcov: don't trace the code coverage code mm: wake kcompactd before kswapd's short sleep .mailmap: add Frank Rowand mm/hwpoison: fix wrong num_poisoned_pages accounting mm: call swap_slot_free_notify() with page lock held mm: vmscan: reclaim highmem zone if buffer_heads is over limit numa: fix /proc/<pid>/numa_maps for THP mm/huge_memory: replace VM_NO_THP VM_BUG_ON with actual VMA check mailmap: fix Krzysztof Kozlowski's misspelled name thp: keep huge zero page pinned until tlb flush mm: exclude HugeTLB pages from THP page_mapped() logic kexec: export OFFSET(page.compound_head) to find out compound tail page kexec: update VMCOREINFO for compound_order/dtor
2016-04-28Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Ingo Molnar: "x86 PMU driver fixes plus a core code race fix" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86/intel: Fix incorrect lbr_sel_mask value perf/x86/intel/pt: Don't die on VMXON perf/core: Fix perf_event_open() vs. execve() race perf/x86/amd: Set the size of event map array to PERF_COUNT_HW_MAX perf/core: Make sysctl_perf_cpu_time_max_percent conform to documentation perf/x86/intel/rapl: Add missing Haswell model perf/x86/intel: Add model number for Skylake Server to perf
2016-04-28Merge branch 'locking-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking fixes from Ingo Molnar: "Two lockdep fixes" * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: lockdep: Fix lock_chain::base size locking/lockdep: Fix ->irq_context calculation
2016-04-28kcov: don't profile branches in kcovAndrey Ryabinin
Profiling 'if' statements in __sanitizer_cov_trace_pc() leads to unbound recursion and crash: __sanitizer_cov_trace_pc() -> ftrace_likely_update -> __sanitizer_cov_trace_pc() ... Define DISABLE_BRANCH_PROFILING to disable this tracer. Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-28kcov: don't trace the code coverage codeJames Morse
Kcov causes the compiler to add a call to __sanitizer_cov_trace_pc() in every basic block. Ftrace patches in a call to _mcount() to each function it has annotated. Letting these mechanisms annotate each other is a bad thing. Break the loop by adding 'notrace' to __sanitizer_cov_trace_pc() so that ftrace won't try to patch this code. This patch lets arm64 with KCOV and STACK_TRACER boot. Signed-off-by: James Morse <james.morse@arm.com> Acked-by: Dmitry Vyukov <dvyukov@google.com> Cc: Alexander Potapenko <glider@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-28kexec: export OFFSET(page.compound_head) to find out compound tail pageAtsushi Kumagai
PageAnon() always look at head page to check PAGE_MAPPING_ANON and tail page's page->mapping has just a poisoned data since commit 1c290f642101 ("mm: sanitize page->mapping for tail pages"). If makedumpfile checks page->mapping of a compound tail page to distinguish anonymous page as usual, it must fail in newer kernel. So it's necessary to export OFFSET(page.compound_head) to avoid checking compound tail pages. The problem is that unnecessary hugepages won't be removed from a dump file in kernels 4.5.x and later. This means that extra disk space would be consumed. It's a problem, but not critical. Signed-off-by: Atsushi Kumagai <ats-kumagai@wm.jp.nec.com> Acked-by: Dave Young <dyoung@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-28kexec: update VMCOREINFO for compound_order/dtorAtsushi Kumagai
makedumpfile refers page.lru.next to get the order of compound pages for page filtering. However, now the order is stored in page.compound_order, hence VMCOREINFO should be updated to export the offset of page.compound_order. The fact is, page.compound_order was introduced already in kernel 4.0, but the offset of it was the same as page.lru.next until kernel 4.3, so this was not actual problem. The above can be said also for page.lru.prev and page.compound_dtor, it's necessary to detect hugetlbfs pages. Further, the content was changed from direct address to the ID which means dtor. The problem is that unnecessary hugepages won't be removed from a dump file in kernels 4.4.x and later. This means that extra disk space would be consumed. It's a problem, but not critical. Signed-off-by: Atsushi Kumagai <ats-kumagai@wm.jp.nec.com> Acked-by: Dave Young <dyoung@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-28bpf: fix check_map_func_compatibility logicAlexei Starovoitov
The commit 35578d798400 ("bpf: Implement function bpf_perf_event_read() that get the selected hardware PMU conuter") introduced clever way to check bpf_helper<->map_type compatibility. Later on commit a43eec304259 ("bpf: introduce bpf_perf_event_output() helper") adjusted the logic and inadvertently broke it. Get rid of the clever bool compare and go back to two-way check from map and from helper perspective. Fixes: a43eec304259 ("bpf: introduce bpf_perf_event_output() helper") Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-28bpf: fix refcnt overflowAlexei Starovoitov
On a system with >32Gbyte of phyiscal memory and infinite RLIMIT_MEMLOCK, the malicious application may overflow 32-bit bpf program refcnt. It's also possible to overflow map refcnt on 1Tb system. Impose 32k hard limit which means that the same bpf program or map cannot be shared by more than 32k processes. Fixes: 1be7f75d1668 ("bpf: enable non-root eBPF programs") Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-28Merge back earlier cpufreq material for v4.7.Rafael J. Wysocki
2016-04-28PM / Hibernate: Call flush_icache_range() on pages restored in-placeJames Morse
Some architectures require code written to memory as if it were data to be 'cleaned' from any data caches before the processor can fetch them as new instructions. During resume from hibernate, the snapshot code copies some pages directly, meaning these architectures do not get a chance to perform their cache maintenance. Modify the read and decompress code to call flush_icache_range() on all pages that are restored, so that the restored in-place pages are guaranteed to be executable on these architectures. Signed-off-by: James Morse <james.morse@arm.com> Acked-by: Pavel Machek <pavel@ucw.cz> Acked-by: Rafael J. Wysocki <rjw@rjwysocki.net> Acked-by: Catalin Marinas <catalin.marinas@arm.com> [will: make clean_pages_on_* static and remove initialisers] Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-04-28sched/core: Add switch_mm_irqs_off() and use it in the schedulerAndy Lutomirski
By default, this is the same thing as switch_mm(). x86 will override it as an optimization. Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: Borislav Petkov <bp@alien8.de> 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/df401df47bdd6be3e389c6f1e3f5310d70e81b2c.1461688545.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-28lcoking/locktorture: Simplify the torture_runnable computationPaul E. McKenney
This commit replaces an #ifdef with IS_ENABLED(), saving five lines. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: corbet@lwn.net Cc: dave@stgolabs.net Cc: dhowells@redhat.com Cc: linux-doc@vger.kernel.org Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1461691328-5429-4-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-28sched/cpufreq: Optimize cpufreq update kicker to avoid update multiple timesWanpeng Li
Sometimes delta_exec is 0 due to update_curr() is called multiple times, this is captured by: u64 delta_exec = rq_clock_task(rq) - curr->se.exec_start; This patch optimizes the cpufreq update kicker by bailing out when nothing changed, it will benefit the upcoming schedutil, since otherwise it will (over)react to the special util/max combination. Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1461316044-9520-1-git-send-email-wanpeng.li@hotmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-28Merge branch 'perf/urgent' into perf/core, to resolve conflictIngo Molnar
Conflicts: arch/x86/events/intel/pt.c Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-28perf/core: Fix perf_event_open() vs. execve() racePeter Zijlstra
Jann reported that the ptrace_may_access() check in find_lively_task_by_vpid() is racy against exec(). Specifically: perf_event_open() execve() ptrace_may_access() commit_creds() ... if (get_dumpable() != SUID_DUMP_USER) perf_event_exit_task(); perf_install_in_context() would result in installing a counter across the creds boundary. Fix this by wrapping lots of perf_event_open() in cred_guard_mutex. This should be fine as perf_event_exit_task() is already called with cred_guard_mutex held, so all perf locks already nest inside it. Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-28nohz/full, sched/rt: Fix missed tick-reenabling bug in sched_can_stop_tick()Peter Zijlstra
Chris Metcalf reported a that sched_can_stop_tick() sometimes fails to re-enable the tick. His observed problem is that rq->cfs.nr_running can be 1 even though there are multiple runnable CFS tasks. This happens in the cgroup case, in which case cfs.nr_running is the number of runnable entities for that level. If there is a single runnable cgroup (which can have an arbitrary number of runnable child entries itself) rq->cfs.nr_running will be 1. However, looking at that function I think there's more problems with it. It seems to assume that if there's FIFO tasks, those will run. This is incorrect. The FIFO task can have a lower prio than an RR task, in which case the RR task will run. So the whole fifo_nr_running test seems misplaced, it should go after the rr_nr_running tests. That is, only if !rr_nr_running, can we use fifo_nr_running like this. Reported-by: Chris Metcalf <cmetcalf@mellanox.com> Tested-by: Chris Metcalf <cmetcalf@mellanox.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Wanpeng Li <kernellwp@gmail.com> Fixes: 76d92ac305f2 ("sched: Migrate sched to use new tick dependency mask model") Link: http://lkml.kernel.org/r/20160421160315.GK24771@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-27Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Minor overlapping changes in the conflicts. In the macsec case, the change of the default ID macro name overlapped with the 64-bit netlink attribute alignment fixes in net-next. Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-27Merge branch 'for-4.6-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq Pull workqueue fix from Tejun Heo: "So, it turns out we had a silly bug in the most fundamental part of workqueue for a very long time. AFAICS, this dates back to pre-git era and has quite likely been there from the time workqueue was first introduced. A work item uses its PENDING bit to synchronize multiple queuers. Anyone who wins the PENDING bit owns the pending state of the work item. Whether a queuer wins or loses the race, one thing should be guaranteed - there will soon be at least one execution of the work item - where "after" means that the execution instance would be able to see all the changes that the queuer has made prior to the queueing attempt. Unfortunately, we were missing a smp_mb() after clearing PENDING for execution, so nothing guaranteed visibility of the changes that a queueing loser has made, which manifested as a reproducible blk-mq stall. Lots of kudos to Roman for debugging the problem. The patch for -stable is the minimal one. For v3.7, Peter is working on a patch to make the code path slightly more efficient and less fragile" * 'for-4.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: fix ghost PENDING flag while doing MQ IO
2016-04-27Merge branch 'for-4.6-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup fixes from Tejun Heo: "Two patches to fix a deadlock which can be easily triggered if memcg charge moving is used. This bug was introduced while converting threadgroup locking to a global percpu_rwsem and is caused by cgroup controller task migration path depending on the ability to create new kthreads. cpuset had a similar issue which was fixed by performing heavy-lifting operations asynchronous to task migration. The two patches fix the same issue in memcg in a similar way. The first patch makes the mechanism generic and the second relocates memcg charge moving outside the migration path. Given that we don't want to perform heavy operations while writelocking threadgroup lock anyway, moving them out of the way is a desirable solution. One thing to note is that the problem was difficult to debug because lockdep couldn't figure out the deadlock condition. Looking into how to improve that" * 'for-4.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: memcg: relocate charge moving from ->attach to ->post_attach cgroup, cpuset: replace cpuset_post_attach_flush() with cgroup_subsys->post_attach callback
2016-04-27Merge branch 'for-mingo' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu Pull RCU updates from Paul E. McKenney: * Documentation updates, including fixes to the design-level requirements documentation and a fixed version of the design-level data-structure documentation. These fixes include removing cartoons and getting rid of the html/htmlx duplication. * Further improvements to the new-age expedited grace periods. * Miscellaneous fixes. * Torture-test changes, including a new rcuperf module for measuring RCU grace-period performance and scalability, which is useful for the expedited-grace-period changes. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-27tracing: Make filter_check_discard() localSteven Rostedt (Red Hat)
Nothing outside of the tracing directory calls filter_check_discard() or check_filter_check_discard(). They should not be called by modules. Move their prototypes into the local tracing header and remove their EXPORT_SYMBOL() macros. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-27perf core: Allow setting up max frame stack depth via sysctlArnaldo Carvalho de Melo
The default remains 127, which is good for most cases, and not even hit most of the time, but then for some cases, as reported by Brendan, 1024+ deep frames are appearing on the radar for things like groovy, ruby. And in some workloads putting a _lower_ cap on this may make sense. One that is per event still needs to be put in place tho. The new file is: # cat /proc/sys/kernel/perf_event_max_stack 127 Chaging it: # echo 256 > /proc/sys/kernel/perf_event_max_stack # cat /proc/sys/kernel/perf_event_max_stack 256 But as soon as there is some event using callchains we get: # echo 512 > /proc/sys/kernel/perf_event_max_stack -bash: echo: write error: Device or resource busy # Because we only allocate the callchain percpu data structures when there is a user, which allows for changing the max easily, its just a matter of having no callchain users at that point. Reported-and-Tested-by: Brendan Gregg <brendan.d.gregg@gmail.com> Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: David Ahern <dsahern@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: He Kuang <hekuang@huawei.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Milian Wolff <milian.wolff@kdab.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: Wang Nan <wangnan0@huawei.com> Cc: Zefan Li <lizefan@huawei.com> Link: http://lkml.kernel.org/r/20160426002928.GB16708@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-04-26tracing: Move event_trigger_unlock_commit{_regs}() to local headerSteven Rostedt (Red Hat)
The functions event_trigger_unlock_commit() and event_trigger_unlock_commit_regs() are no longer used outside the tracing system. Move them out of the generic headers and into the local one. Along with __event_trigger_test_discard() that is only used by them. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-27ftrace: Match dot symbols when searching functions on ppc64Thiago Jung Bauermann
In the ppc64 big endian ABI, function symbols point to function descriptors. The symbols which point to the function entry points have a dot in front of the function name. Consequently, when the ftrace filter mechanism searches for the symbol corresponding to an entry point address, it gets the dot symbol. As a result, ftrace filter users have to be aware of this ABI detail on ppc64 and prepend a dot to the function name when setting the filter. The perf probe command insulates the user from this by ignoring the dot in front of the symbol name when matching function names to symbols, but the sysfs interface does not. This patch makes the ftrace filter mechanism do the same when searching symbols. Fixes the following failure in ftracetest's kprobe_ftrace.tc: .../kprobe_ftrace.tc: line 9: echo: write error: Invalid argument That failure is on this line of kprobe_ftrace.tc: echo _do_fork > set_ftrace_filter This is because there's no _do_fork entry in the functions list: # cat available_filter_functions | grep _do_fork ._do_fork This change introduces no regressions on the perf and ftracetest testsuite results. Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-04-26Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds
Pull networking fixes from David Miller: 1) Handle v4/v6 mixed sockets properly in soreuseport, from Craig Gallak. 2) Bug fixes for the new macsec facility (missing kmalloc NULL checks, missing locking around netdev list traversal, etc.) from Sabrina Dubroca. 3) Fix handling of host routes on ifdown in ipv6, from David Ahern. 4) Fix double-fdput in bpf verifier. From Jann Horn. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (31 commits) bpf: fix double-fdput in replace_map_fd_with_map_ptr() net: ipv6: Delete host routes on an ifdown Revert "ipv6: Revert optional address flusing on ifdown." net/mlx4_en: fix spurious timestamping callbacks net: dummy: remove note about being Y by default cxgbi: fix uninitialized flowi6 ipv6: Revert optional address flusing on ifdown. ipv4/fib: don't warn when primary address is missing if in_dev is dead net/mlx5: Add pci shutdown callback net/mlx5_core: Remove static from local variable net/mlx5e: Use vport MTU rather than physical port MTU net/mlx5e: Fix minimum MTU net/mlx5e: Device's mtu field is u16 and not int net/mlx5_core: Add ConnectX-5 to list of supported devices net/mlx5e: Fix MLX5E_100BASE_T define net/mlx5_core: Fix soft lockup in steering error flow qlcnic: Update version to 5.3.64 net: stmmac: socfpga: Remove re-registration of reset controller macsec: fix netlink attribute validation macsec: add missing macsec prefix in uapi ...
2016-04-26bpf: fix double-fdput in replace_map_fd_with_map_ptr()Jann Horn
When bpf(BPF_PROG_LOAD, ...) was invoked with a BPF program whose bytecode references a non-map file descriptor as a map file descriptor, the error handling code called fdput() twice instead of once (in __bpf_map_get() and in replace_map_fd_with_map_ptr()). If the file descriptor table of the current task is shared, this causes f_count to be decremented too much, allowing the struct file to be freed while it is still in use (use-after-free). This can be exploited to gain root privileges by an unprivileged user. This bug was introduced in commit 0246e64d9a5f ("bpf: handle pseudo BPF_LD_IMM64 insn"), but is only exploitable since commit 1be7f75d1668 ("bpf: enable non-root eBPF programs") because previously, CAP_SYS_ADMIN was required to reach the vulnerable code. (posted publicly according to request by maintainer) Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-26audit: add tty field to LOGIN eventRichard Guy Briggs
The tty field was missing from AUDIT_LOGIN events. Refactor code to create a new function audit_get_tty(), using it to replace the call in audit_log_task_info() and to add it to audit_log_set_loginuid(). Lock and bump the kref to protect it, adding audit_put_tty() alias to decrement it. Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-04-26tracing: Don't use the address of the buffer array name in copy_from_userWang Xiaoqiang
With the following code snippet: ... char buf[64]; ... if (copy_from_user(&buf, ubuf, cnt)) ... Even though the value of "&buf" equals "buf", but there is no need to get the address of the "buf" again. Use "buf" instead of "&buf". Link: http://lkml.kernel.org/r/20160418152329.18b72bea@debian Signed-off-by: Wang Xiaoqiang <wangxq10@lzu.edu.cn> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-26workqueue: fix ghost PENDING flag while doing MQ IORoman Pen
The bug in a workqueue leads to a stalled IO request in MQ ctx->rq_list with the following backtrace: [ 601.347452] INFO: task kworker/u129:5:1636 blocked for more than 120 seconds. [ 601.347574] Tainted: G O 4.4.5-1-storage+ #6 [ 601.347651] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 601.348142] kworker/u129:5 D ffff880803077988 0 1636 2 0x00000000 [ 601.348519] Workqueue: ibnbd_server_fileio_wq ibnbd_dev_file_submit_io_worker [ibnbd_server] [ 601.348999] ffff880803077988 ffff88080466b900 ffff8808033f9c80 ffff880803078000 [ 601.349662] ffff880807c95000 7fffffffffffffff ffffffff815b0920 ffff880803077ad0 [ 601.350333] ffff8808030779a0 ffffffff815b01d5 0000000000000000 ffff880803077a38 [ 601.350965] Call Trace: [ 601.351203] [<ffffffff815b0920>] ? bit_wait+0x60/0x60 [ 601.351444] [<ffffffff815b01d5>] schedule+0x35/0x80 [ 601.351709] [<ffffffff815b2dd2>] schedule_timeout+0x192/0x230 [ 601.351958] [<ffffffff812d43f7>] ? blk_flush_plug_list+0xc7/0x220 [ 601.352208] [<ffffffff810bd737>] ? ktime_get+0x37/0xa0 [ 601.352446] [<ffffffff815b0920>] ? bit_wait+0x60/0x60 [ 601.352688] [<ffffffff815af784>] io_schedule_timeout+0xa4/0x110 [ 601.352951] [<ffffffff815b3a4e>] ? _raw_spin_unlock_irqrestore+0xe/0x10 [ 601.353196] [<ffffffff815b093b>] bit_wait_io+0x1b/0x70 [ 601.353440] [<ffffffff815b056d>] __wait_on_bit+0x5d/0x90 [ 601.353689] [<ffffffff81127bd0>] wait_on_page_bit+0xc0/0xd0 [ 601.353958] [<ffffffff81096db0>] ? autoremove_wake_function+0x40/0x40 [ 601.354200] [<ffffffff81127cc4>] __filemap_fdatawait_range+0xe4/0x140 [ 601.354441] [<ffffffff81127d34>] filemap_fdatawait_range+0x14/0x30 [ 601.354688] [<ffffffff81129a9f>] filemap_write_and_wait_range+0x3f/0x70 [ 601.354932] [<ffffffff811ced3b>] blkdev_fsync+0x1b/0x50 [ 601.355193] [<ffffffff811c82d9>] vfs_fsync_range+0x49/0xa0 [ 601.355432] [<ffffffff811cf45a>] blkdev_write_iter+0xca/0x100 [ 601.355679] [<ffffffff81197b1a>] __vfs_write+0xaa/0xe0 [ 601.355925] [<ffffffff81198379>] vfs_write+0xa9/0x1a0 [ 601.356164] [<ffffffff811c59d8>] kernel_write+0x38/0x50 The underlying device is a null_blk, with default parameters: queue_mode = MQ submit_queues = 1 Verification that nullb0 has something inflight: root@pserver8:~# cat /sys/block/nullb0/inflight 0 1 root@pserver8:~# find /sys/block/nullb0/mq/0/cpu* -name rq_list -print -exec cat {} \; ... /sys/block/nullb0/mq/0/cpu2/rq_list CTX pending: ffff8838038e2400 ... During debug it became clear that stalled request is always inserted in the rq_list from the following path: save_stack_trace_tsk + 34 blk_mq_insert_requests + 231 blk_mq_flush_plug_list + 281 blk_flush_plug_list + 199 wait_on_page_bit + 192 __filemap_fdatawait_range + 228 filemap_fdatawait_range + 20 filemap_write_and_wait_range + 63 blkdev_fsync + 27 vfs_fsync_range + 73 blkdev_write_iter + 202 __vfs_write + 170 vfs_write + 169 kernel_write + 56 So blk_flush_plug_list() was called with from_schedule == true. If from_schedule is true, that means that finally blk_mq_insert_requests() offloads execution of __blk_mq_run_hw_queue() and uses kblockd workqueue, i.e. it calls kblockd_schedule_delayed_work_on(). That means, that we race with another CPU, which is about to execute __blk_mq_run_hw_queue() work. Further debugging shows the following traces from different CPUs: CPU#0 CPU#1 ---------------------------------- ------------------------------- reqeust A inserted STORE hctx->ctx_map[0] bit marked kblockd_schedule...() returns 1 <schedule to kblockd workqueue> request B inserted STORE hctx->ctx_map[1] bit marked kblockd_schedule...() returns 0 *** WORK PENDING bit is cleared *** flush_busy_ctxs() is executed, but bit 1, set by CPU#1, is not observed As a result request B pended forever. This behaviour can be explained by speculative LOAD of hctx->ctx_map on CPU#0, which is reordered with clear of PENDING bit and executed _before_ actual STORE of bit 1 on CPU#1. The proper fix is an explicit full barrier <mfence>, which guarantees that clear of PENDING bit is to be executed before all possible speculative LOADS or STORES inside actual work function. Signed-off-by: Roman Pen <roman.penyaev@profitbricks.com> Cc: Gioh Kim <gi-oh.kim@profitbricks.com> Cc: Michael Wang <yun.wang@profitbricks.com> Cc: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: linux-block@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by: Tejun Heo <tj@kernel.org>
2016-04-26tracing: Handle tracing_map_alloc_elts() error path correctlyTom Zanussi
If tracing_map_elt_alloc() fails, it will return ERR_PTR() instead of NULL, so change the check to IS_ERROR(). We also need to set the failed entry in the map->elts array to NULL instead of ERR_PTR() so tracing_map_free_elts() doesn't try freeing an ERR_PTR(). tracing_map_free_elts() should also zero out what it frees so a reentrant call won't find previously freed elements. Link: http://lkml.kernel.org/r/f29d03b00bce3aac8cf151a8a30e6c83e5fee66d.1461610073.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>