- 25 8月, 2017 2 次提交
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由 Peter Zijlstra 提交于
Mike provided a better comment for destroy_sched_domain() ... Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NIngo Molnar <mingo@kernel.org>
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由 Shu Wang 提交于
Found this issue by kmemleak: the 'sg' and 'sgc' pointers from __sdt_alloc() might be leaked as each domain holds many groups' ref, but in destroy_sched_domain(), it only declined the first group ref. Onlining and offlining a CPU can trigger this leak, and cause OOM. Reproducer for my 6 CPUs machine: while true do echo 0 > /sys/devices/system/cpu/cpu5/online; echo 1 > /sys/devices/system/cpu/cpu5/online; done unreferenced object 0xffff88007d772a80 (size 64): comm "cpuhp/5", pid 39, jiffies 4294719962 (age 35.251s) hex dump (first 32 bytes): c0 22 77 7d 00 88 ff ff 02 00 00 00 01 00 00 00 ."w}............ 40 2a 77 7d 00 88 ff ff 00 00 00 00 00 00 00 00 @*w}............ backtrace: [<ffffffff8176525a>] kmemleak_alloc+0x4a/0xa0 [<ffffffff8121efe1>] __kmalloc_node+0xf1/0x280 [<ffffffff810d94a8>] build_sched_domains+0x1e8/0xf20 [<ffffffff810da674>] partition_sched_domains+0x304/0x360 [<ffffffff81139557>] cpuset_update_active_cpus+0x17/0x40 [<ffffffff810bdb2e>] sched_cpu_activate+0xae/0xc0 [<ffffffff810900e0>] cpuhp_invoke_callback+0x90/0x400 [<ffffffff81090597>] cpuhp_up_callbacks+0x37/0xb0 [<ffffffff81090887>] cpuhp_thread_fun+0xd7/0xf0 [<ffffffff810b37e0>] smpboot_thread_fn+0x110/0x160 [<ffffffff810af5d9>] kthread+0x109/0x140 [<ffffffff81770e45>] ret_from_fork+0x25/0x30 [<ffffffffffffffff>] 0xffffffffffffffff unreferenced object 0xffff88007d772a40 (size 64): comm "cpuhp/5", pid 39, jiffies 4294719962 (age 35.251s) hex dump (first 32 bytes): 03 00 00 00 00 00 00 00 00 04 00 00 00 00 00 00 ................ 00 04 00 00 00 00 00 00 4f 3c fc ff 00 00 00 00 ........O<...... backtrace: [<ffffffff8176525a>] kmemleak_alloc+0x4a/0xa0 [<ffffffff8121efe1>] __kmalloc_node+0xf1/0x280 [<ffffffff810da16d>] build_sched_domains+0xead/0xf20 [<ffffffff810da674>] partition_sched_domains+0x304/0x360 [<ffffffff81139557>] cpuset_update_active_cpus+0x17/0x40 [<ffffffff810bdb2e>] sched_cpu_activate+0xae/0xc0 [<ffffffff810900e0>] cpuhp_invoke_callback+0x90/0x400 [<ffffffff81090597>] cpuhp_up_callbacks+0x37/0xb0 [<ffffffff81090887>] cpuhp_thread_fun+0xd7/0xf0 [<ffffffff810b37e0>] smpboot_thread_fn+0x110/0x160 [<ffffffff810af5d9>] kthread+0x109/0x140 [<ffffffff81770e45>] ret_from_fork+0x25/0x30 [<ffffffffffffffff>] 0xffffffffffffffff Reported-by: NChunyu Hu <chuhu@redhat.com> Signed-off-by: NShu Wang <shuwang@redhat.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Acked-by: NChunyu Hu <chuhu@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: liwang@redhat.com Link: http://lkml.kernel.org/r/1502351536-9108-1-git-send-email-shuwang@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 24 8月, 2017 3 次提交
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由 Steven Rostedt (VMware) 提交于
Performing the following task with kmemleak enabled: # cd /sys/kernel/tracing/events/irq/irq_handler_entry/ # echo 'enable_event:kmem:kmalloc:3 if irq >' > trigger # echo 'enable_event:kmem:kmalloc:3 if irq > 31' > trigger # echo scan > /sys/kernel/debug/kmemleak # cat /sys/kernel/debug/kmemleak unreferenced object 0xffff8800b9290308 (size 32): comm "bash", pid 1114, jiffies 4294848451 (age 141.139s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff81cef5aa>] kmemleak_alloc+0x4a/0xa0 [<ffffffff81357938>] kmem_cache_alloc_trace+0x158/0x290 [<ffffffff81261c09>] create_filter_start.constprop.28+0x99/0x940 [<ffffffff812639c9>] create_filter+0xa9/0x160 [<ffffffff81263bdc>] create_event_filter+0xc/0x10 [<ffffffff812655e5>] set_trigger_filter+0xe5/0x210 [<ffffffff812660c4>] event_enable_trigger_func+0x324/0x490 [<ffffffff812652e2>] event_trigger_write+0x1a2/0x260 [<ffffffff8138cf87>] __vfs_write+0xd7/0x380 [<ffffffff8138f421>] vfs_write+0x101/0x260 [<ffffffff8139187b>] SyS_write+0xab/0x130 [<ffffffff81cfd501>] entry_SYSCALL_64_fastpath+0x1f/0xbe [<ffffffffffffffff>] 0xffffffffffffffff The function create_filter() is passed a 'filterp' pointer that gets allocated, and if "set_str" is true, it is up to the caller to free it, even on error. The problem is that the pointer is not freed by create_filter() when set_str is false. This is a bug, and it is not up to the caller to free the filter on error if it doesn't care about the string. Link: http://lkml.kernel.org/r/1502705898-27571-2-git-send-email-chuhu@redhat.com Cc: stable@vger.kernel.org Fixes: 38b78eb8 ("tracing: Factorize filter creation") Reported-by: NChunyu Hu <chuhu@redhat.com> Tested-by: NChunyu Hu <chuhu@redhat.com> Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
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由 Chunyu Hu 提交于
kmemleak reported the below leak when I was doing clear of the hist trigger. With this patch, the kmeamleak is gone. unreferenced object 0xffff94322b63d760 (size 32): comm "bash", pid 1522, jiffies 4403687962 (age 2442.311s) hex dump (first 32 bytes): 00 01 00 00 04 00 00 00 08 00 00 00 ff 00 00 00 ................ 10 00 00 00 00 00 00 00 80 a8 7a f2 31 94 ff ff ..........z.1... backtrace: [<ffffffff9e96c27a>] kmemleak_alloc+0x4a/0xa0 [<ffffffff9e424cba>] kmem_cache_alloc_trace+0xca/0x1d0 [<ffffffff9e377736>] tracing_map_array_alloc+0x26/0x140 [<ffffffff9e261be0>] kretprobe_trampoline+0x0/0x50 [<ffffffff9e38b935>] create_hist_data+0x535/0x750 [<ffffffff9e38bd47>] event_hist_trigger_func+0x1f7/0x420 [<ffffffff9e38893d>] event_trigger_write+0xfd/0x1a0 [<ffffffff9e44dfc7>] __vfs_write+0x37/0x170 [<ffffffff9e44f552>] vfs_write+0xb2/0x1b0 [<ffffffff9e450b85>] SyS_write+0x55/0xc0 [<ffffffff9e203857>] do_syscall_64+0x67/0x150 [<ffffffff9e977ce7>] return_from_SYSCALL_64+0x0/0x6a [<ffffffffffffffff>] 0xffffffffffffffff unreferenced object 0xffff9431f27aa880 (size 128): comm "bash", pid 1522, jiffies 4403687962 (age 2442.311s) hex dump (first 32 bytes): 00 00 8c 2a 32 94 ff ff 00 f0 8b 2a 32 94 ff ff ...*2......*2... 00 e0 8b 2a 32 94 ff ff 00 d0 8b 2a 32 94 ff ff ...*2......*2... backtrace: [<ffffffff9e96c27a>] kmemleak_alloc+0x4a/0xa0 [<ffffffff9e425348>] __kmalloc+0xe8/0x220 [<ffffffff9e3777c1>] tracing_map_array_alloc+0xb1/0x140 [<ffffffff9e261be0>] kretprobe_trampoline+0x0/0x50 [<ffffffff9e38b935>] create_hist_data+0x535/0x750 [<ffffffff9e38bd47>] event_hist_trigger_func+0x1f7/0x420 [<ffffffff9e38893d>] event_trigger_write+0xfd/0x1a0 [<ffffffff9e44dfc7>] __vfs_write+0x37/0x170 [<ffffffff9e44f552>] vfs_write+0xb2/0x1b0 [<ffffffff9e450b85>] SyS_write+0x55/0xc0 [<ffffffff9e203857>] do_syscall_64+0x67/0x150 [<ffffffff9e977ce7>] return_from_SYSCALL_64+0x0/0x6a [<ffffffffffffffff>] 0xffffffffffffffff Link: http://lkml.kernel.org/r/1502705898-27571-1-git-send-email-chuhu@redhat.com Cc: stable@vger.kernel.org Fixes: 08d43a5f ("tracing: Add lock-free tracing_map") Signed-off-by: NChunyu Hu <chuhu@redhat.com> Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
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由 Steven Rostedt (VMware) 提交于
There's a small race when function graph shutsdown and the calling of the registered function graph entry callback. The callback must not reference the task's ret_stack without first checking that it is not NULL. Note, when a ret_stack is allocated for a task, it stays allocated until the task exits. The problem here, is that function_graph is shutdown, and a new task was created, which doesn't have its ret_stack allocated. But since some of the functions are still being traced, the callbacks can still be called. The normal function_graph code handles this, but starting with commit 8861dd30 ("ftrace: Access ret_stack->subtime only in the function profiler") the profiler code references the ret_stack on function entry, but doesn't check if it is NULL first. Link: https://bugzilla.kernel.org/show_bug.cgi?id=196611 Cc: stable@vger.kernel.org Fixes: 8861dd30 ("ftrace: Access ret_stack->subtime only in the function profiler") Reported-by: lilydjwg@gmail.com Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
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- 22 8月, 2017 1 次提交
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由 Oleg Nesterov 提交于
This was reported many times, and this was even mentioned in commit 52ee2dfd ("pids: refactor vnr/nr_ns helpers to make them safe") but somehow nobody bothered to fix the obvious problem: task_tgid_nr_ns() is not safe because task->group_leader points to nowhere after the exiting task passes exit_notify(), rcu_read_lock() can not help. We really need to change __unhash_process() to nullify group_leader, parent, and real_parent, but this needs some cleanups. Until then we can turn task_tgid_nr_ns() into another user of __task_pid_nr_ns() and fix the problem. Reported-by: NTroy Kensinger <tkensinger@google.com> Signed-off-by: NOleg Nesterov <oleg@redhat.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 20 8月, 2017 1 次提交
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由 Alexey Dobriyan 提交于
Valid CPU ids are [0, nr_cpu_ids-1] inclusive. Fixes: 3b8e29a8 ("genirq: Implement ipi_send_mask/single()") Fixes: f9bce791 ("genirq: Add a new function to get IPI reverse mapping") Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20170819095751.GB27864@avx2
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- 19 8月, 2017 2 次提交
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由 Jamie Iles 提交于
When forcing a signal, SIGNAL_UNKILLABLE is removed to prevent recursive faults, but this is undesirable when tracing. For example, debugging an init process (whether global or namespace), hitting a breakpoint and SIGTRAP will force SIGTRAP and then remove SIGNAL_UNKILLABLE. Everything continues fine, but then once debugging has finished, the init process is left killable which is unlikely what the user expects, resulting in either an accidentally killed init or an init that stops reaping zombies. Link: http://lkml.kernel.org/r/20170815112806.10728-1-jamie.iles@oracle.comSigned-off-by: NJamie Iles <jamie.iles@oracle.com> Acked-by: NOleg Nesterov <oleg@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Luis R. Rodriguez 提交于
Recursive loops with module loading were previously handled in kmod by restricting the number of modprobe calls to 50 and if that limit was breached request_module() would return an error and a user would see the following on their kernel dmesg: request_module: runaway loop modprobe binfmt-464c Starting init:/sbin/init exists but couldn't execute it (error -8) This issue could happen for instance when a 64-bit kernel boots a 32-bit userspace on some architectures and has no 32-bit binary format hanlders. This is visible, for instance, when a CONFIG_MODULES enabled 64-bit MIPS kernel boots a into o32 root filesystem and the binfmt handler for o32 binaries is not built-in. After commit 6d7964a7 ("kmod: throttle kmod thread limit") we now don't have any visible signs of an error and the kernel just waits for the loop to end somehow. Although this *particular* recursive loop could also be addressed by doing a sanity check on search_binary_handler() and disallowing a modular binfmt to be required for modprobe, a generic solution for any recursive kernel kmod issues is still needed. This should catch these loops. We can investigate each loop and address each one separately as they come in, this however puts a stop gap for them as before. Link: http://lkml.kernel.org/r/20170809234635.13443-3-mcgrof@kernel.org Fixes: 6d7964a7 ("kmod: throttle kmod thread limit") Signed-off-by: NLuis R. Rodriguez <mcgrof@kernel.org> Reported-by: NMatt Redfearn <matt.redfearn@imgtec.com> Tested-by: NMatt Redfearn <matt.redfearn@imgetc.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Daniel Mentz <danielmentz@google.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jessica Yu <jeyu@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Michal Marek <mmarek@suse.com> Cc: Miroslav Benes <mbenes@suse.cz> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 18 8月, 2017 2 次提交
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由 Thomas Gleixner 提交于
The hardlockup detector on x86 uses a performance counter based on unhalted CPU cycles and a periodic hrtimer. The hrtimer period is about 2/5 of the performance counter period, so the hrtimer should fire 2-3 times before the performance counter NMI fires. The NMI code checks whether the hrtimer fired since the last invocation. If not, it assumess a hard lockup. The calculation of those periods is based on the nominal CPU frequency. Turbo modes increase the CPU clock frequency and therefore shorten the period of the perf/NMI watchdog. With extreme Turbo-modes (3x nominal frequency) the perf/NMI period is shorter than the hrtimer period which leads to false positives. A simple fix would be to shorten the hrtimer period, but that comes with the side effect of more frequent hrtimer and softlockup thread wakeups, which is not desired. Implement a low pass filter, which checks the perf/NMI period against kernel time. If the perf/NMI fires before 4/5 of the watchdog period has elapsed then the event is ignored and postponed to the next perf/NMI. That solves the problem and avoids the overhead of shorter hrtimer periods and more frequent softlockup thread wakeups. Fixes: 58687acb ("lockup_detector: Combine nmi_watchdog and softlockup detector") Reported-and-tested-by: NKan Liang <Kan.liang@intel.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Cc: dzickus@redhat.com Cc: prarit@redhat.com Cc: ak@linux.intel.com Cc: babu.moger@oracle.com Cc: peterz@infradead.org Cc: eranian@google.com Cc: acme@redhat.com Cc: stable@vger.kernel.org Cc: atomlin@redhat.com Cc: akpm@linux-foundation.org Cc: torvalds@linux-foundation.org Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1708150931310.1886@nanos
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由 Marc Zyngier 提交于
irq_modify_status starts by clearing the trigger settings from irq_data before applying the new settings, but doesn't restore them, leaving them to IRQ_TYPE_NONE. That's pretty confusing to the potential request_irq() that could follow. Instead, snapshot the settings before clearing them, and restore them if the irq_modify_status() invocation was not changing the trigger. Fixes: 1e2a7d78 ("irqdomain: Don't set type when mapping an IRQ") Reported-and-tested-by: Njeffy <jeffy.chen@rock-chips.com> Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Cc: Jon Hunter <jonathanh@nvidia.com> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20170818095345.12378-1-marc.zyngier@arm.com
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- 17 8月, 2017 1 次提交
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由 Steven Rostedt 提交于
The complete_all() function modifies the completion's "done" variable to UINT_MAX, and no other caller (wait_for_completion(), etc) will modify it back to zero. That means that any call to complete_all() must have a reinit_completion() before that completion can be used again. Document this fact by the complete_all() function. Also document that completion_done() will always return true if complete_all() is called. Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org> Acked-by: NLinus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170816131202.195c2f4b@gandalf.local.homeSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 16 8月, 2017 3 次提交
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由 Daniel Borkmann 提交于
James reported that on MIPS32 bpf_trace_printk() is currently broken while MIPS64 works fine: bpf_trace_printk() uses conditional operators to attempt to pass different types to __trace_printk() depending on the format operators. This doesn't work as intended on 32-bit architectures where u32 and long are passed differently to u64, since the result of C conditional operators follows the "usual arithmetic conversions" rules, such that the values passed to __trace_printk() will always be u64 [causing issues later in the va_list handling for vscnprintf()]. For example the samples/bpf/tracex5 test printed lines like below on MIPS32, where the fd and buf have come from the u64 fd argument, and the size from the buf argument: [...] 1180.941542: 0x00000001: write(fd=1, buf= (null), size=6258688) Instead of this: [...] 1625.616026: 0x00000001: write(fd=1, buf=009e4000, size=512) One way to get it working is to expand various combinations of argument types into 8 different combinations for 32 bit and 64 bit kernels. Fix tested by James on MIPS32 and MIPS64 as well that it resolves the issue. Fixes: 9c959c86 ("tracing: Allow BPF programs to call bpf_trace_printk()") Reported-by: NJames Hogan <james.hogan@imgtec.com> Tested-by: NJames Hogan <james.hogan@imgtec.com> Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Jan Kara 提交于
Although audit_watch_handle_event() can handle FS_UNMOUNT event, it is not part of AUDIT_FS_WATCH mask and thus such event never gets to audit_watch_handle_event(). Thus fsnotify marks are deleted by fsnotify subsystem on unmount without audit being notified about that which leads to a strange state of existing audit rules with dead fsnotify marks. Add FS_UNMOUNT to the mask of events to be received so that audit can clean up its state accordingly. Signed-off-by: NJan Kara <jack@suse.cz> Signed-off-by: NPaul Moore <paul@paul-moore.com>
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由 Jan Kara 提交于
audit_remove_watch_rule() drops watch's reference to parent but then continues to work with it. That is not safe as parent can get freed once we drop our reference. The following is a trivial reproducer: mount -o loop image /mnt touch /mnt/file auditctl -w /mnt/file -p wax umount /mnt auditctl -D <crash in fsnotify_destroy_mark()> Grab our own reference in audit_remove_watch_rule() earlier to make sure mark does not get freed under us. CC: stable@vger.kernel.org Reported-by: NTony Jones <tonyj@suse.de> Signed-off-by: NJan Kara <jack@suse.cz> Tested-by: NTony Jones <tonyj@suse.de> Signed-off-by: NPaul Moore <paul@paul-moore.com>
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- 11 8月, 2017 2 次提交
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由 Nadav Amit 提交于
Patch series "fixes of TLB batching races", v6. It turns out that Linux TLB batching mechanism suffers from various races. Races that are caused due to batching during reclamation were recently handled by Mel and this patch-set deals with others. The more fundamental issue is that concurrent updates of the page-tables allow for TLB flushes to be batched on one core, while another core changes the page-tables. This other core may assume a PTE change does not require a flush based on the updated PTE value, while it is unaware that TLB flushes are still pending. This behavior affects KSM (which may result in memory corruption) and MADV_FREE and MADV_DONTNEED (which may result in incorrect behavior). A proof-of-concept can easily produce the wrong behavior of MADV_DONTNEED. Memory corruption in KSM is harder to produce in practice, but was observed by hacking the kernel and adding a delay before flushing and replacing the KSM page. Finally, there is also one memory barrier missing, which may affect architectures with weak memory model. This patch (of 7): Setting and clearing mm->tlb_flush_pending can be performed by multiple threads, since mmap_sem may only be acquired for read in task_numa_work(). If this happens, tlb_flush_pending might be cleared while one of the threads still changes PTEs and batches TLB flushes. This can lead to the same race between migration and change_protection_range() that led to the introduction of tlb_flush_pending. The result of this race was data corruption, which means that this patch also addresses a theoretically possible data corruption. An actual data corruption was not observed, yet the race was was confirmed by adding assertion to check tlb_flush_pending is not set by two threads, adding artificial latency in change_protection_range() and using sysctl to reduce kernel.numa_balancing_scan_delay_ms. Link: http://lkml.kernel.org/r/20170802000818.4760-2-namit@vmware.com Fixes: 20841405 ("mm: fix TLB flush race between migration, and change_protection_range") Signed-off-by: NNadav Amit <namit@vmware.com> Acked-by: NMel Gorman <mgorman@suse.de> Acked-by: NRik van Riel <riel@redhat.com> Acked-by: NMinchan Kim <minchan@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Russell King <linux@armlinux.org.uk> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Johannes Weiner 提交于
As Tetsuo points out: "Commit 385386cf ("mm: vmstat: move slab statistics from zone to node counters") broke "Slab:" field of /proc/meminfo . It shows nearly 0kB" In addition to /proc/meminfo, this problem also affects the slab counters OOM/allocation failure info dumps, can cause early -ENOMEM from overcommit protection, and miscalculate image size requirements during suspend-to-disk. This is because the patch in question switched the slab counters from the zone level to the node level, but forgot to update the global accessor functions to read the aggregate node data instead of the aggregate zone data. Use global_node_page_state() to access the global slab counters. Fixes: 385386cf ("mm: vmstat: move slab statistics from zone to node counters") Link: http://lkml.kernel.org/r/20170801134256.5400-1-hannes@cmpxchg.orgSigned-off-by: NJohannes Weiner <hannes@cmpxchg.org> Reported-by: NTetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Acked-by: NMichal Hocko <mhocko@suse.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Stefan Agner <stefan@agner.ch> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 10 8月, 2017 23 次提交
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由 Anshuman Khandual 提交于
Its kzalloc() not kmalloc() which has failed earlier. While here remove a redundant empty line. Signed-off-by: NAnshuman Khandual <khandual@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20170802084300.29487-1-khandual@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Peter Zijlstra 提交于
In commit: 3fed382b ("sched/numa: Implement NUMA node level wake_affine()") Rik changed wake_affine to consider NUMA information when balancing between LLC domains. There are a number of problems here which this patch tries to address: - LLC < NODE; in this case we'd use the wrong information to balance - !NUMA_BALANCING: in this case, the new code doesn't do any balancing at all - re-computes the NUMA data for every wakeup, this can mean iterating up to 64 CPUs for every wakeup. - default affine wakeups inside a cache We address these by saving the load/capacity values for each sched_domain during regular load-balance and using these values in wake_affine_llc(). The obvious down-side to using cached values is that they can be too old and poorly reflect reality. But this way we can use LLC wide information and thus not rely on assuming LLC matches NODE. We also don't rely on NUMA_BALANCING nor do we have to aggegate two nodes (or even cache domains) worth of CPUs for each wakeup. Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Fixes: 3fed382b ("sched/numa: Implement NUMA node level wake_affine()") [ Minor readability improvements. ] Signed-off-by: NIngo Molnar <mingo@kernel.org>
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由 Xie XiuQi 提交于
Now that we have more than one place to get the task state, intruduce the task_state_to_char() helper function to save some code. No functionality changed. Signed-off-by: NXie XiuQi <xiexiuqi@huawei.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: <cj.chengjian@huawei.com> Cc: <huawei.libin@huawei.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/1502095463-160172-3-git-send-email-xiexiuqi@huawei.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Xie XiuQi 提交于
Currently we print the runnable task in /proc/sched_debug, but there is no task state information. We don't know which task is in the runqueue and which task is sleeping. Add task state in the runnable task list, like this: runnable tasks: S task PID tree-key switches prio wait-time sum-exec sum-sleep ----------------------------------------------------------------------------------------------------------- S watchdog/239 1452 -11.917445 2811 0 0.000000 8.949306 0.000000 7 0 / S migration/239 1453 20686.367740 8 0 0.000000 16215.720897 0.000000 7 0 / S ksoftirqd/239 1454 115383.841071 12 120 0.000000 0.200683 0.000000 7 0 / >R test 21287 4872.190970 407 120 0.000000 4874.911790 0.000000 7 0 /autogroup-150 R test 21288 4868.385454 401 120 0.000000 3672.341489 0.000000 7 0 /autogroup-150 R test 21289 4868.326776 384 120 0.000000 3424.934159 0.000000 7 0 /autogroup-150 Signed-off-by: NXie XiuQi <xiexiuqi@huawei.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: <cj.chengjian@huawei.com> Cc: <huawei.libin@huawei.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/1502095463-160172-2-git-send-email-xiexiuqi@huawei.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Aleksa Sarai 提交于
It appears as though the addition of the PID namespace did not update the output code for /proc/*/sched, which resulted in it providing PIDs that were not self-consistent with the /proc mount. This additionally made it trivial to detect whether a process was inside &init_pid_ns from userspace, making container detection trivial: https://github.com/jessfraz/amicontained This leads to situations such as: % unshare -pmf % mount -t proc proc /proc % head -n1 /proc/1/sched head (10047, #threads: 1) Fix this by just using task_pid_nr_ns for the output of /proc/*/sched. All of the other uses of task_pid_nr in kernel/sched/debug.c are from a sysctl context and thus don't need to be namespaced. Signed-off-by: NAleksa Sarai <asarai@suse.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Acked-by: NEric W. Biederman <ebiederm@xmission.com> Cc: Jess Frazelle <acidburn@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: cyphar@cyphar.com Link: http://lkml.kernel.org/r/20170806044141.5093-1-asarai@suse.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Cheng Jian 提交于
init_idle_bootup_task( ) is called in rest_init( ) to switch the scheduling class of the boot thread to the idle class. the function only sets: idle->sched_class = &idle_sched_class; which has been set in init_idle() called by sched_init(): /* * The idle tasks have their own, simple scheduling class: */ idle->sched_class = &idle_sched_class; We've already set the boot thread to idle class in start_kernel()->sched_init()->init_idle() so it's unnecessary to set it again in start_kernel()->rest_init()->init_idle_bootup_task() Signed-off-by: NCheng Jian <cj.chengjian@huawei.com> Signed-off-by: NXie XiuQi <xiexiuqi@huawei.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: <akpm@linux-foundation.org> Cc: <huawei.libin@huawei.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/1501838377-109720-1-git-send-email-cj.chengjian@huawei.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Byungchul Park 提交于
cpudl_find() users are only interested in knowing if suitable CPU(s) were found or not (and then they look at later_mask to know which). Change cpudl_find() return type accordingly. Aligns with rt code. Signed-off-by: NByungchul Park <byungchul.park@lge.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: <bristot@redhat.com> Cc: <juri.lelli@gmail.com> Cc: <kernel-team@lge.com> Cc: <rostedt@goodmis.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/1495504859-10960-3-git-send-email-byungchul.park@lge.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Byungchul Park 提交于
When cpudl_find() returns any among free_cpus, the CPU might not be closer than others, considering sched domain. For example: this_cpu: 15 free_cpus: 0, 1,..., 14 (== later_mask) best_cpu: 0 topology: 0 --+ +--+ 1 --+ | +-- ... --+ 2 --+ | | +--+ | 3 --+ | ... ... 12 --+ | +--+ | 13 --+ | | +-- ... -+ 14 --+ | +--+ 15 --+ In this case, it would be best to select 14 since it's a free CPU and closest to 15 (this_cpu). However, currently the code selects 0 (best_cpu) even though that's just any among free_cpus. Fix it. This (re)aligns the deadline behaviour with the rt behaviour. Signed-off-by: NByungchul Park <byungchul.park@lge.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: <bristot@redhat.com> Cc: <juri.lelli@gmail.com> Cc: <kernel-team@lge.com> Cc: <rostedt@goodmis.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/1495504859-10960-2-git-send-email-byungchul.park@lge.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Rik van Riel 提交于
Running 80 tasks in the same group, or as threads of the same process, results in the memory getting scanned 80x as fast as it would be if a single task was using the memory. This really hurts some workloads. Scale the scan period by the number of tasks in the numa group, and the shared / private ratio, so the average rate at which memory in the group is scanned corresponds roughly to the rate at which a single task would scan its memory. Signed-off-by: NRik van Riel <riel@redhat.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Acked-by: NMel Gorman <mgorman@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: jhladky@redhat.com Cc: lvenanci@redhat.com Link: http://lkml.kernel.org/r/20170731192847.23050-3-riel@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Rik van Riel 提交于
The comment above update_task_scan_period() says the scan period should be increased (scanning slows down) if the majority of memory accesses are on the local node, or if the majority of the page accesses are shared with other tasks. However, with the current code, all a high ratio of shared accesses does is slow down the rate at which scanning is made faster. This patch changes things so either lots of shared accesses or lots of local accesses will slow down scanning, and numa scanning is sped up only when there are lots of private faults on remote memory pages. Signed-off-by: NRik van Riel <riel@redhat.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Acked-by: NMel Gorman <mgorman@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: jhladky@redhat.com Cc: lvenanci@redhat.com Link: http://lkml.kernel.org/r/20170731192847.23050-2-riel@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Vincent Guittot 提交于
The running state is a subset of runnable state which means that running can't be set if runnable (weight) is cleared. There are corner cases where the current sched_entity has been already dequeued but cfs_rq->curr has not been updated yet and still points to the dequeued sched_entity. If ___update_load_avg() is called at that time, weight will be 0 and running will be set which is not possible. This case happens during pick_next_task_fair() when a cfs_rq becomes idles. The current sched_entity has been dequeued so se->on_rq is cleared and cfs_rq->weight is null. But cfs_rq->curr still points to se (it will be cleared when picking the idle thread). Because the cfs_rq becomes idle, idle_balance() is called and ends up to call update_blocked_averages() with these wrong running and runnable states. Add a test in ___update_load_avg() to correct the running state in this case. Signed-off-by: NVincent Guittot <vincent.guittot@linaro.org> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten.Rasmussen@arm.com Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dietmar.eggemann@arm.com Link: http://lkml.kernel.org/r/1498885573-18984-1-git-send-email-vincent.guittot@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Viresh Kumar 提交于
pick_next_task_dl() and build_sched_domain() aren't used outside deadline.c and topology.c. Make them static. Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org> Signed-off-by: NPeter 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: Vincent Guittot <vincent.guittot@linaro.org> Cc: linaro-kernel@lists.linaro.org Link: http://lkml.kernel.org/r/36e4cbb6210002cadae89920ae97e19e7e513008.1493281605.git.viresh.kumar@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Viresh Kumar 提交于
The 'struct cpupri' passed to cpupri_init() is already initialized to zero. Don't do that again. Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org> Signed-off-by: NPeter 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: Vincent Guittot <vincent.guittot@linaro.org> Cc: linaro-kernel@lists.linaro.org Link: http://lkml.kernel.org/r/8a71d48c5a077500b6ddc1a41484c0ac8d3aad94.1492065513.git.viresh.kumar@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Viresh Kumar 提交于
The 'struct cpudl' passed to cpudl_init() is already initialized to zero. Don't do that again. Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org> Signed-off-by: NPeter 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: Vincent Guittot <vincent.guittot@linaro.org> Cc: linaro-kernel@lists.linaro.org Link: http://lkml.kernel.org/r/bd4c229806bc96694b15546207afcc221387d2f5.1492065513.git.viresh.kumar@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Viresh Kumar 提交于
There are only two callers of init_rootdomain(). One of them passes a global to it and another one sends dynamically allocated root-domain. There is no need to memset the root-domain in the first case as the structure is already reset. Update alloc_rootdomain() to allocate the memory with kzalloc() and remove the memset() call from init_rootdomain(). Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org> Signed-off-by: NPeter 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: Vincent Guittot <vincent.guittot@linaro.org> Cc: linaro-kernel@lists.linaro.org Link: http://lkml.kernel.org/r/fc2f6cc90b098040970c85a97046512572d765bc.1492065513.git.viresh.kumar@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Viresh Kumar 提交于
update_freq is always true and there is no need to pass it to update_cfs_rq_load_avg(). Remove it. Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org> Signed-off-by: NPeter 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: Vincent Guittot <vincent.guittot@linaro.org> Cc: linaro-kernel@lists.linaro.org Link: http://lkml.kernel.org/r/2d28d295f3f591ede7e931462bce1bda5aaa4896.1495603536.git.viresh.kumar@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Viresh Kumar 提交于
Rearrange pick_next_task_fair() a bit to avoid checking cfs_rq->nr_running twice for the case where FAIR_GROUP_SCHED is enabled and the previous task doesn't belong to the fair class. Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org> Signed-off-by: NPeter 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: Vincent Guittot <vincent.guittot@linaro.org> Cc: linaro-kernel@lists.linaro.org Link: http://lkml.kernel.org/r/000903ab3df3350943d3271c53615893a230dc95.1495603536.git.viresh.kumar@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Viresh Kumar 提交于
weighted_cpuload() uses the cpu number passed to it get pointer to the runqueue. Almost all callers of weighted_cpuload() already have the rq pointer with them and can send that directly to weighted_cpuload(). In some cases the callers actually get the CPU number by doing cpu_of(rq). It would be simpler to pass rq to weighted_cpuload(). Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org> Signed-off-by: NPeter 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: Vincent Guittot <vincent.guittot@linaro.org> Cc: linaro-kernel@lists.linaro.org Link: http://lkml.kernel.org/r/b7720627e0576dc29b4ba3f9b6edbc913bb4f684.1495603536.git.viresh.kumar@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Viresh Kumar 提交于
Reuse put_prev_task() instead of copying its implementation. Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org> Signed-off-by: NPeter 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: Vincent Guittot <vincent.guittot@linaro.org> Cc: linaro-kernel@lists.linaro.org Link: http://lkml.kernel.org/r/e2e50578223d05c5e90a9feb964fe1ec5d09a052.1495603536.git.viresh.kumar@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Viresh Kumar 提交于
For SMP systems, update_load_avg() calls the cpufreq update util handlers only for the top level cfs_rq (i.e. rq->cfs). But that is not the case for UP systems. update_load_avg() calls util handler for any cfs_rq for which it is called. This would result in way too many calls from the scheduler to the cpufreq governors when CONFIG_FAIR_GROUP_SCHED is enabled. Reduce the frequency of these calls by copying the behavior from the SMP case, i.e. Only call util handlers for the top level cfs_rq. Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org> Signed-off-by: NPeter 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: Vincent Guittot <vincent.guittot@linaro.org> Cc: linaro-kernel@lists.linaro.org Fixes: 536bd00c ("sched/fair: Fix !CONFIG_SMP kernel cpufreq governor breakage") Link: http://lkml.kernel.org/r/6abf69a2107525885b616a2c1ec03d9c0946171c.1495603536.git.viresh.kumar@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Peter Zijlstra 提交于
Vince reported that when we do IOC_ENABLE/IOC_DISABLE while the task is SIGSTOP'ed state the timestamps go wobbly. It turns out we indeed fail to correctly account time while in 'OFF' state and doing IOC_ENABLE without getting scheduled in exposes the problem. Further thinking about this problem, it occurred to me that we can suffer a similar fate when we migrate an uncore event between CPUs. The perf_event_install() on the 'new' CPU will do add_event_to_ctx() which will reset all the time stamp, resulting in a subsequent update_event_times() to overwrite the total_time_* fields with smaller values. Reported-by: NVince Weaver <vincent.weaver@maine.edu> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NIngo Molnar <mingo@kernel.org>
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由 Peter Zijlstra 提交于
Vince reported the following rdpmc() testcase failure: > Failing test case: > > fd=perf_event_open(); > addr=mmap(fd); > exec() // without closing or unmapping the event > fd=perf_event_open(); > addr=mmap(fd); > rdpmc() // GPFs due to rdpmc being disabled The problem is of course that exec() plays tricks with what is current->mm, only destroying the old mappings after having installed the new mm. Fix this confusion by passing along vma->vm_mm instead of relying on current->mm. Reported-by: NVince Weaver <vincent.weaver@maine.edu> Tested-by: NVince Weaver <vincent.weaver@maine.edu> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: NAndy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Fixes: 1e0fb9ec ("perf: Add pmu callbacks to track event mapping and unmapping") Link: http://lkml.kernel.org/r/20170802173930.cstykcqefmqt7jau@hirez.programming.kicks-ass.net [ Minor cleanups. ] Signed-off-by: NIngo Molnar <mingo@kernel.org>
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由 Mel Gorman 提交于
Commit 65d8fc77 ("futex: Remove requirement for lock_page() in get_futex_key()") removed an unnecessary lock_page() with the side-effect that page->mapping needed to be treated very carefully. Two defensive warnings were added in case any assumption was missed and the first warning assumed a correct application would not alter a mapping backing a futex key. Since merging, it has not triggered for any unexpected case but Mark Rutland reported the following bug triggering due to the first warning. kernel BUG at kernel/futex.c:679! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 3695 Comm: syz-executor1 Not tainted 4.13.0-rc3-00020-g307fec773ba3 #3 Hardware name: linux,dummy-virt (DT) task: ffff80001e271780 task.stack: ffff000010908000 PC is at get_futex_key+0x6a4/0xcf0 kernel/futex.c:679 LR is at get_futex_key+0x6a4/0xcf0 kernel/futex.c:679 pc : [<ffff00000821ac14>] lr : [<ffff00000821ac14>] pstate: 80000145 The fact that it's a bug instead of a warning was due to an unrelated arm64 problem, but the warning itself triggered because the underlying mapping changed. This is an application issue but from a kernel perspective it's a recoverable situation and the warning is unnecessary so this patch removes the warning. The warning may potentially be triggered with the following test program from Mark although it may be necessary to adjust NR_FUTEX_THREADS to be a value smaller than the number of CPUs in the system. #include <linux/futex.h> #include <pthread.h> #include <stdio.h> #include <stdlib.h> #include <sys/mman.h> #include <sys/syscall.h> #include <sys/time.h> #include <unistd.h> #define NR_FUTEX_THREADS 16 pthread_t threads[NR_FUTEX_THREADS]; void *mem; #define MEM_PROT (PROT_READ | PROT_WRITE) #define MEM_SIZE 65536 static int futex_wrapper(int *uaddr, int op, int val, const struct timespec *timeout, int *uaddr2, int val3) { syscall(SYS_futex, uaddr, op, val, timeout, uaddr2, val3); } void *poll_futex(void *unused) { for (;;) { futex_wrapper(mem, FUTEX_CMP_REQUEUE_PI, 1, NULL, mem + 4, 1); } } int main(int argc, char *argv[]) { int i; mem = mmap(NULL, MEM_SIZE, MEM_PROT, MAP_SHARED | MAP_ANONYMOUS, -1, 0); printf("Mapping @ %p\n", mem); printf("Creating futex threads...\n"); for (i = 0; i < NR_FUTEX_THREADS; i++) pthread_create(&threads[i], NULL, poll_futex, NULL); printf("Flipping mapping...\n"); for (;;) { mmap(mem, MEM_SIZE, MEM_PROT, MAP_FIXED | MAP_SHARED | MAP_ANONYMOUS, -1, 0); } return 0; } Reported-and-tested-by: NMark Rutland <mark.rutland@arm.com> Signed-off-by: NMel Gorman <mgorman@suse.de> Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: stable@vger.kernel.org # 4.7+ Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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