aboutsummaryrefslogtreecommitdiffstats
path: root/kernel
AgeCommit message (Collapse)AuthorFilesLines
2017-09-19signal: lift sigset size check out of do_sigpending()Dmitry V. Levin1-7/+14
As sigsetsize argument of do_sigpending() is not used anywhere else in that function after the check, remove this argument and move the check out of do_sigpending() into rt_sigpending() and its compat analog. Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Dmitry V. Levin <ldv@altlinux.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-09-19signal: simplify compat_sigpending()Dmitry V. Levin1-4/+0
Remove "if it's big-endian..." ifdef in compat_sigpending(), use the endian-agnostic variant. Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Dmitry V. Levin <ldv@altlinux.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-09-19signal: replace sigset_to_compat() with put_compat_sigset()Dmitry V. Levin2-27/+20
There are 4 callers of sigset_to_compat() in the entire kernel. One is in sparc compat rt_sigaction(2), the rest are in kernel/signal.c itself. All are followed by copy_to_user(), and all but the sparc one are under "if it's big-endian..." ifdefs. Let's transform sigset_to_compat() into put_compat_sigset() that also calls copy_to_user(). Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Dmitry V. Levin <ldv@altlinux.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-09-19bpf: Implement map_delete_elem for BPF_MAP_TYPE_LPM_TRIECraig Gallek1-3/+77
This is a simple non-recursive delete operation. It prunes paths of empty nodes in the tree, but it does not try to further compress the tree as nodes are removed. Signed-off-by: Craig Gallek <kraig@google.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-19tracing: Ignore mmiotrace from kernel commandlineZiqian SUN (Zamir)3-0/+10
The mmiotrace tracer cannot be enabled with ftrace=mmiotrace in kernel commandline. With this patch, noboot is added to the tracer struct, and when system boot with a tracer that has noboot=true, it will print out a warning message and continue booting. Link: http://lkml.kernel.org/r/1505111195-31942-1-git-send-email-zsun@redhat.com Signed-off-by: Ziqian SUN (Zamir) <zsun@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2017-09-19tracing: Erase irqsoff trace with empty writeBo Yan1-2/+8
One convenient way to erase trace is "echo > trace". However, this is currently broken if the current tracer is irqsoff tracer. This is because irqsoff tracer use max_buffer as the default trace buffer. Set the max_buffer as the one to be cleared when it's the trace buffer currently in use. Link: http://lkml.kernel.org/r/1505754215-29411-1-git-send-email-byan@nvidia.com Cc: <mingo@redhat.com> Cc: stable@vger.kernel.org Fixes: 4acd4d00f ("tracing: give easy way to clear trace buffer") Signed-off-by: Bo Yan <byan@nvidia.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2017-09-18bpf: devmap: pass on return value of bpf_map_precharge_memlockTobias Klauser1-2/+4
If bpf_map_precharge_memlock in dev_map_alloc, -ENOMEM is returned regardless of the actual error produced by bpf_map_precharge_memlock. Fix it by passing on the error returned by bpf_map_precharge_memlock. Also return -EINVAL instead of -ENOMEM if the page count overflow check fails. This makes dev_map_alloc match the behavior of other bpf maps' alloc functions wrt. return values. Signed-off-by: Tobias Klauser <tklauser@distanz.ch> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-17Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds1-1/+1
Pull irq fix from Thomas Gleixner: "Fix for an off by one error in a cpumask result comparison" * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: genirq: Fix cpumask check in __irq_startup_managed()
2017-09-16Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds2-2/+3
Pull networking fixes from David Miller: 1) Fix hotplug deadlock in hv_netvsc, from Stephen Hemminger. 2) Fix double-free in rmnet driver, from Dan Carpenter. 3) INET connection socket layer can double put request sockets, fix from Eric Dumazet. 4) Don't match collect metadata-mode tunnels if the device is down, from Haishuang Yan. 5) Do not perform TSO6/GSO on ipv6 packets with extensions headers in be2net driver, from Suresh Reddy. 6) Fix scaling error in gen_estimator, from Eric Dumazet. 7) Fix 64-bit statistics deadlock in systemport driver, from Florian Fainelli. 8) Fix use-after-free in sctp_sock_dump, from Xin Long. 9) Reject invalid BPF_END instructions in verifier, from Edward Cree. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (43 commits) mlxsw: spectrum_router: Only handle IPv4 and IPv6 events Documentation: link in networking docs tcp: fix data delivery rate bpf/verifier: reject BPF_ALU64|BPF_END sctp: do not mark sk dumped when inet_sctp_diag_fill returns err sctp: fix an use-after-free issue in sctp_sock_dump netvsc: increase default receive buffer size tcp: update skb->skb_mstamp more carefully net: ipv4: fix l3slave check for index returned in IP_PKTINFO net: smsc911x: Quieten netif during suspend net: systemport: Fix 64-bit stats deadlock net: vrf: avoid gcc-4.6 warning qed: remove unnecessary call to memset tg3: clean up redundant initialization of tnapi tls: make tls_sw_free_resources static sctp: potential read out of bounds in sctp_ulpevent_type_enabled() MAINTAINERS: review Renesas DT bindings as well net_sched: gen_estimator: fix scaling error in bytes/packets samples nfp: wait for the NSP resource to appear on boot nfp: wait for board state before talking to the NSP ...
2017-09-16genirq: Fix cpumask check in __irq_startup_managed()Thomas Gleixner1-1/+1
The result of cpumask_any_and() is invalid when result greater or equal nr_cpu_ids. The current check is checking for greater only. Fix it. Fixes: 761ea388e8c4 ("genirq: Handle managed irqs gracefully in irq_startup()") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Juergen Gross <jgross@suse.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Chen Yu <yu.c.chen@intel.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Alok Kataria <akataria@vmware.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: stable@vger.kernel.org Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rui Zhang <rui.zhang@intel.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Len Brown <lenb@kernel.org> Link: http://lkml.kernel.org/r/20170913213152.272283444@linutronix.de
2017-09-15bpf/verifier: reject BPF_ALU64|BPF_ENDEdward Cree1-1/+2
Neither ___bpf_prog_run nor the JITs accept it. Also adds a new test case. Fixes: 17a5267067f3 ("bpf: verifier (add verifier core)") Signed-off-by: Edward Cree <ecree@solarflare.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-15livepatch: __klp_shadow_get_or_alloc() is local to shadow.cJiri Kosina1-1/+1
... therefore make it static. Fixes: 439e7271dc2 ("livepatch: introduce shadow variable API") Acked-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2017-09-14Merge branch 'work.set_fs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfsLinus Torvalds2-8/+15
Pull more set_fs removal from Al Viro: "Christoph's 'use kernel_read and friends rather than open-coding set_fs()' series" * 'work.set_fs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fs: unexport vfs_readv and vfs_writev fs: unexport vfs_read and vfs_write fs: unexport __vfs_read/__vfs_write lustre: switch to kernel_write gadget/f_mass_storage: stop messing with the address limit mconsole: switch to kernel_read btrfs: switch write_buf to kernel_write net/9p: switch p9_fd_read to kernel_write mm/nommu: switch do_mmap_private to kernel_read serial2002: switch serial2002_tty_write to kernel_{read/write} fs: make the buf argument to __kernel_write a void pointer fs: fix kernel_write prototype fs: fix kernel_read prototype fs: move kernel_read to fs/read_write.c fs: move kernel_write to fs/read_write.c autofs4: switch autofs4_write to __kernel_write ashmem: switch to ->read_iter
2017-09-14Merge branch 'work.ipc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfsLinus Torvalds3-30/+7
Pull ipc compat cleanup and 64-bit time_t from Al Viro: "IPC copyin/copyout sanitizing, including 64bit time_t work from Deepa Dinamani" * 'work.ipc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: utimes: Make utimes y2038 safe ipc: shm: Make shmid_kernel timestamps y2038 safe ipc: sem: Make sem_array timestamps y2038 safe ipc: msg: Make msg_queue timestamps y2038 safe ipc: mqueue: Replace timespec with timespec64 ipc: Make sys_semtimedop() y2038 safe get rid of SYSVIPC_COMPAT on ia64 semtimedop(): move compat to native shmat(2): move compat to native msgrcv(2), msgsnd(2): move compat to native ipc(2): move compat to native ipc: make use of compat ipc_perm helpers semctl(): move compat to native semctl(): separate all layout-dependent copyin/copyout msgctl(): move compat to native msgctl(): split the actual work from copyin/copyout ipc: move compat shmctl to native shmctl: split the work from copyin/copyout
2017-09-14livepatch: introduce shadow variable APIJoe Lawrence2-1/+278
Add exported API for livepatch modules: klp_shadow_get() klp_shadow_alloc() klp_shadow_get_or_alloc() klp_shadow_free() klp_shadow_free_all() that implement "shadow" variables, which allow callers to associate new shadow fields to existing data structures. This is intended to be used by livepatch modules seeking to emulate additions to data structure definitions. See Documentation/livepatch/shadow-vars.txt for a summary of the new shadow variable API, including a few common use cases. See samples/livepatch/livepatch-shadow-* for example modules that demonstrate shadow variables. [jkosina@suse.cz: fix __klp_shadow_get_or_alloc() comment as spotted by Josh] Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2017-09-14Merge branch 'akpm' (patches from Andrew)Linus Torvalds2-2/+2
Merge misc fixes from Andrew Morton: "A few leftovers" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: mm, page_owner: skip unnecessary stack_trace entries arm64: stacktrace: avoid listing stacktrace functions in stacktrace mm: treewide: remove GFP_TEMPORARY allocation flag IB/mlx4: fix sprintf format warning fscache: fix fscache_objlist_show format processing lib/test_bitmap.c: use ULL suffix for 64-bit constants procfs: remove unused variable drivers/media/cec/cec-adap.c: fix build with gcc-4.4.4 idr: remove WARN_ON_ONCE() when trying to replace negative ID
2017-09-14sched/wait: Introduce wakeup boomark in wake_up_page_bitTim Chen1-0/+7
Now that we have added breaks in the wait queue scan and allow bookmark on scan position, we put this logic in the wake_up_page_bit function. We can have very long page wait list in large system where multiple pages share the same wait list. We break the wake up walk here to allow other cpus a chance to access the list, and not to disable the interrupts when traversing the list for too long. This reduces the interrupt and rescheduling latency, and excessive page wait queue lock hold time. [ v2: Remove bookmark_wake_function ] Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-14sched/wait: Break up long wake list walkTim Chen1-15/+63
We encountered workloads that have very long wake up list on large systems. A waker takes a long time to traverse the entire wake list and execute all the wake functions. We saw page wait list that are up to 3700+ entries long in tests of large 4 and 8 socket systems. It took 0.8 sec to traverse such list during wake up. Any other CPU that contends for the list spin lock will spin for a long time. It is a result of the numa balancing migration of hot pages that are shared by many threads. Multiple CPUs waking are queued up behind the lock, and the last one queued has to wait until all CPUs did all the wakeups. The page wait list is traversed with interrupt disabled, which caused various problems. This was the original cause that triggered the NMI watch dog timer in: https://patchwork.kernel.org/patch/9800303/ . Only extending the NMI watch dog timer there helped. This patch bookmarks the waker's scan position in wake list and break the wake up walk, to allow access to the list before the waker resume its walk down the rest of the wait list. It lowers the interrupt and rescheduling latency. This patch also provides a performance boost when combined with the next patch to break up page wakeup list walk. We saw 22% improvement in the will-it-scale file pread2 test on a Xeon Phi system running 256 threads. [ v2: Merged in Linus' changes to remove the bookmark_wake_function, and simply access to flags. ] Reported-by: Kan Liang <kan.liang@intel.com> Tested-by: Kan Liang <kan.liang@intel.com> Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-14watchdog/hardlockup: Clean up hotplug locking messThomas Gleixner1-6/+0
All watchdog thread related functions are delegated to the smpboot thread infrastructure, which handles serialization against CPU hotplug correctly. The sysctl interface is completely decoupled from anything which requires CPU hotplug protection. No need to protect the sysctl writes against cpu hotplug anymore. Remove it and add the now required protection to the powerpc arch_nmi_watchdog implementation. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/20170912194148.418497420@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/hardlockup/perf: Simplify deferred event destroyThomas Gleixner1-5/+2
Now that all functionality is properly serialized against CPU hotplug, remove the extra per cpu storage which holds the disabled events for cleanup. The core makes sure that cleanup happens before new events are created. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194148.340708074@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/hardlockup/perf: Use new perf CPU enable mechanismThomas Gleixner2-84/+8
Get rid of the hodgepodge which tries to be smart about perf being unavailable and error printout rate limiting. That's all not required simply because this is never invoked when the perf NMI watchdog is not functional. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194148.259651788@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/hardlockup/perf: Implement CPU enable replacementThomas Gleixner1-0/+11
watchdog_nmi_enable() is an unparseable mess, Provide a clean perf specific implementation, which will be used when the existing setup/teardown mess is replaced. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194148.180215498@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/hardlockup/perf: Implement init time detection of perfThomas Gleixner1-1/+12
Use the init time detection of the perf NMI watchdog to determine whether the perf NMI watchdog is functional. If not disable it permanentely. It won't come back magically at runtime. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194148.099799541@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/hardlockup/perf: Implement init time perf validationThomas Gleixner1-0/+37
The watchdog tries to create perf events even after it figured out that perf is not functional or the requested event is not supported. That's braindead as this can be done once at init time and if not supported the NMI watchdog can be turned off unconditonally. Implement the perf hardlockup detector functionality for that. This creates a new event create function, which will replace the unholy mess of the existing one in later patches. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194148.019090547@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/core: Get rid of the racy update loopThomas Gleixner1-48/+47
Letting user space poke directly at variables which are used at run time is stupid and causes a lot of race conditions and other issues. Seperate the user variables and on change invoke the reconfiguration, which then stops the watchdogs, reevaluates the new user value and restarts the watchdogs with the new parameters. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194147.939985640@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/core, powerpc: Make watchdog_nmi_reconfigure() two stageThomas Gleixner1-9/+22
Both the perf reconfiguration and the powerpc watchdog_nmi_reconfigure() need to be done in two steps. 1) Stop all NMIs 2) Read the new parameters and start NMIs Right now watchdog_nmi_reconfigure() is a combination of both. To allow a clean reconfiguration add a 'run' argument and split the functionality in powerpc. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/20170912194147.862865570@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/sysctl: Clean up sysctl variable name spaceThomas Gleixner2-29/+28
Reflect that these variables are user interface related and remove the whitespace damage in the sysctl table while at it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194147.783210221@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/sysctl: Get rid of the #ifdefferyThomas Gleixner1-5/+1
The sysctl of the nmi_watchdog file prevents writes by setting: min = max = 0 if none of the users is enabled. That involves ifdeffery and is competely non obvious. If none of the facilities is enabeld, then the file can simply be made read only. Move the ifdeffery into the header and use a constant for file permissions. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194147.706073616@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/core: Further simplify sysctl handlingThomas Gleixner1-20/+7
Use a single function to update sysctl changes. This is not a high frequency user space interface and it's root only. Preparatory patch to cleanup the sysctl variable handling. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194147.549114957@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/core: Get rid of the thread teardown/setup danceThomas Gleixner1-171/+19
The lockup detector reconfiguration tears down all watchdog threads when the watchdog is disabled and sets them up again when its enabled. That's a pointless exercise. The watchdog threads are not consuming an insane amount of resources, so it's enough to set them up at init time and keep them in parked position when the watchdog is disabled and unpark them when it is reenabled. The smpboot thread infrastructure takes care of keeping the force parked threads in place even across cpu hotplug. Aside of that the code implements the park/unpark facility of smp hotplug threads on its own, which is even more pointless. We have functionality in the smpboot thread code to do so. Use the new thread management functions and get rid of the unholy mess. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194147.470370113@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/core: Create new thread handling infrastructureThomas Gleixner1-0/+75
The lockup detector reconfiguration tears down all watchdog threads when the watchdog is disabled and sets them up again when its enabled. That's a pointless exercise. The watchdog threads are not consuming an insane amount of resources, so it's enough to set them up at init time and keep them in parked position when the watchdog is disabled and unpark them when it is reenabled. The smpboot thread infrastructure takes care of keeping the force parked threads in place even across cpu hotplug. Another horrible mechanism are the open coded park/unpark loops which are used for reconfiguration of the watchdog. The smpboot infrastructure allows exactly the same via smpboot_update_cpumask_thread_percpu(), which is cpu hotplug safe. Using that instead of the open coded loops allows to get rid of the hotplug locking mess in the watchdog code. Implement a clean infrastructure which allows to replace the open coded nonsense. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194147.377182587@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14smpboot/threads, watchdog/core: Avoid runtime allocationThomas Gleixner2-31/+12
smpboot_update_cpumask_threads_percpu() allocates a temporary cpumask at runtime. This is suboptimal because the call site needs more code size for proper error handling than a statically allocated temporary mask requires data size. Add static temporary cpumask. The function is globaly serialized, so no further protection required. Remove the half baken error handling in the watchdog code and get rid of the export as there are no in tree modular users of that function. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194147.297288838@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/core: Split out cpumask write functionThomas Gleixner1-19/+21
Split the write part of the cpumask proc handler out into a separate helper to avoid deep indentation. This also reduces the patch complexity in the following cleanups. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194147.218075991@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/core: Clean up the #ifdef mazeThomas Gleixner1-20/+13
The #ifdef maze in this file is horrible, group stuff at least a bit so one can figure out what belongs to what. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194147.139629546@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/core: Clean up stub functionsThomas Gleixner1-46/+22
Having stub functions which take a full page is not helping the readablility of code. Condense them and move the doubled #ifdef variant into the SYSFS section. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194147.045545271@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/core: Remove the park_in_progress obfuscationThomas Gleixner2-25/+19
Commit: b94f51183b06 ("kernel/watchdog: prevent false hardlockup on overloaded system") tries to fix the following issue: proc_write() set_sample_period() <--- New sample period becoms visible <----- Broken starts proc_watchdog_update() watchdog_enable_all_cpus() watchdog_hrtimer_fn() update_watchdog_all_cpus() restart_timer(sample_period) watchdog_park_threads() thread->park() disable_nmi() <----- Broken ends The reason why this is broken is that the update of the watchdog threshold becomes immediately effective and visible for the hrtimer function which uses that value to rearm the timer. But the NMI/perf side still uses the old value up to the point where it is disabled. If the rate has been lowered then the NMI can run fast enough to 'detect' a hard lockup because the timer has not fired due to the longer period. The patch 'fixed' this by adding a variable: proc_write() set_sample_period() <----- Broken starts proc_watchdog_update() watchdog_enable_all_cpus() watchdog_hrtimer_fn() update_watchdog_all_cpus() restart_timer(sample_period) watchdog_park_threads() park_in_progress = 1 <----- Broken ends nmi_watchdog() if (park_in_progress) return; The only effect of this variable was to make the window where the breakage can hit small enough that it was not longer observable in testing. From a correctness point of view it is a pointless bandaid which merily papers over the root cause: the unsychronized update of the variable. Looking deeper into the related code pathes unearthed similar problems in the watchdog_start()/stop() functions. watchdog_start() perf_nmi_event_start() hrtimer_start() watchdog_stop() hrtimer_cancel() perf_nmi_event_stop() In both cases the call order is wrong because if the tasks gets preempted or the VM gets scheduled out long enough after the first call, then there is a chance that the next NMI will see a stale hrtimer interrupt count and trigger a false positive hard lockup splat. Get rid of park_in_progress so the code can be gradually deobfuscated and pruned from several layers of duct tape papering over the root cause, which has been either ignored or not understood at all. Once this is removed the underlying problem will be fixed by rewriting the proc interface to do a proper synchronized update. Address the start/stop() ordering problem as well by reverting the call order, so this part is at least correct now. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1709052038270.2393@nanos Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/hardlockup/perf: Prevent CPU hotplug deadlockThomas Gleixner3-6/+59
The following deadlock is possible in the watchdog hotplug code: cpus_write_lock() ... takedown_cpu() smpboot_park_threads() smpboot_park_thread() kthread_park() ->park() := watchdog_disable() watchdog_nmi_disable() perf_event_release_kernel(); put_event() _free_event() ->destroy() := hw_perf_event_destroy() x86_release_hardware() release_ds_buffers() get_online_cpus() when a per cpu watchdog perf event is destroyed which drops the last reference to the PMU hardware. The cleanup code there invokes get_online_cpus() which instantly deadlocks because the hotplug percpu rwsem is write locked. To solve this add a deferring mechanism: cpus_write_lock() kthread_park() watchdog_nmi_disable(deferred) perf_event_disable(event); move_event_to_deferred(event); .... cpus_write_unlock() cleaup_deferred_events() perf_event_release_kernel() This is still properly serialized against concurrent hotplug via the cpu_add_remove_lock, which is held by the task which initiated the hotplug event. This is also used to handle event destruction when the watchdog threads are parked via other mechanisms than CPU hotplug. Analyzed-by: Peter Zijlstra <peterz@infradead.org> Reported-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194146.884469246@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/hardlockup/perf: Remove broken self disable on failureThomas Gleixner2-28/+7
The self disabling feature is broken vs. CPU hotplug locking: CPU 0 CPU 1 cpus_write_lock(); cpu_up(1) wait_for_completion() .... unpark_watchdog() ->unpark() perf_event_create() <- fails watchdog_enable &= ~NMI_WATCHDOG; .... cpus_write_unlock(); CPU 2 cpus_write_lock() cpu_down(2) wait_for_completion() wakeup(watchdog); watchdog() if (!(watchdog_enable & NMI_WATCHDOG)) watchdog_nmi_disable() perf_event_disable() .... cpus_read_lock(); stop_smpboot_threads() park_watchdog(); wait_for_completion(watchdog->parked); Result: End of hotplug and instantaneous full lockup of the machine. There is a similar problem with disabling the watchdog via the user space interface as the sysctl function fiddles with watchdog_enable directly. It's very debatable whether this is required at all. If the watchdog works nicely on N CPUs and it fails to enable on the N + 1 CPU either during hotplug or because the user space interface disabled it via sysctl cpumask and then some perf user grabbed the counter which is then unavailable for the watchdog when the sysctl cpumask gets changed back. There is no real justification for this. One of the reasons WHY this is done is the utter stupidity of the init code of the perf NMI watchdog. Instead of checking upfront at boot whether PERF is available and functional at all, it just does this check at run time over and over when user space fiddles with the sysctl. That's broken beyond repair along with the idiotic error code dependent warn level printks and the even more silly printk rate limiting. If the init code checks whether perf works at boot time, then this mess can be more or less avoided completely. Perf does not come magically into life at runtime. Brain usage while coding is overrated. Remove the cruft and add a temporary safe guard which gets removed later. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194146.806708429@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/core: Mark hardlockup_detector_disable() __initThomas Gleixner1-1/+1
The function is only used by the KVM init code. Mark it __init to prevent creative abuse. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194146.727134632@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/core: Rename watchdog_proc_mutexThomas Gleixner1-8/+7
Following patches will use the mutex for other purposes as well. Rename it as it is not longer a proc specific thing. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194146.647714850@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/core: Rework CPU hotplug lockingThomas Gleixner1-6/+6
The watchdog proc interface causes extensive recursive locking of the CPU hotplug percpu rwsem, which is deadlock prone. Replace the get/put_online_cpus() pairs with cpu_hotplug_disable()/enable() calls for now. Later patches will remove that requirement completely. Reported-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194146.568079057@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/core: Remove broken suspend/resume interfacesThomas Gleixner1-88/+1
This interface has several issues: - It's causing recursive locking of the hotplug lock. - It's complete overkill to teardown all threads and then recreate them The same can be achieved with the simple hardlockup_detector_perf_stop / restart() interfaces. The abuse from the busy looping poweroff() loop of PARISC has been solved as well. Remove the cruft. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194146.487537732@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/core: Provide interface to stop from poweroff()Thomas Gleixner1-1/+13
PARISC has a a busy looping power off routine. If the watchdog is enabled the watchdog timer will still fire, but the thread is not running, which causes the softlockup watchdog to trigger. Provide a interface which allows to turn the watchdog off. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Helge Deller <deller@gmx.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Cc: linux-parisc@vger.kernel.org Link: http://lkml.kernel.org/r/20170912194146.327343752@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14watchdog/hardlockup: Provide interface to stop/restart perf eventsPeter Zijlstra1-0/+41
Provide an interface to stop and restart perf NMI watchdog events on all CPUs. This is only usable during init and especially for handling the perf HT bug on Intel machines. It's safe to use it this way as nothing can start/stop the NMI watchdog in parallel. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194146.167649596@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-13mm: treewide: remove GFP_TEMPORARY allocation flagMichal Hocko2-2/+2
GFP_TEMPORARY was introduced by commit e12ba74d8ff3 ("Group short-lived and reclaimable kernel allocations") along with __GFP_RECLAIMABLE. It's primary motivation was to allow users to tell that an allocation is short lived and so the allocator can try to place such allocations close together and prevent long term fragmentation. As much as this sounds like a reasonable semantic it becomes much less clear when to use the highlevel GFP_TEMPORARY allocation flag. How long is temporary? Can the context holding that memory sleep? Can it take locks? It seems there is no good answer for those questions. The current implementation of GFP_TEMPORARY is basically GFP_KERNEL | __GFP_RECLAIMABLE which in itself is tricky because basically none of the existing caller provide a way to reclaim the allocated memory. So this is rather misleading and hard to evaluate for any benefits. I have checked some random users and none of them has added the flag with a specific justification. I suspect most of them just copied from other existing users and others just thought it might be a good idea to use without any measuring. This suggests that GFP_TEMPORARY just motivates for cargo cult usage without any reasoning. I believe that our gfp flags are quite complex already and especially those with highlevel semantic should be clearly defined to prevent from confusion and abuse. Therefore I propose dropping GFP_TEMPORARY and replace all existing users to simply use GFP_KERNEL. Please note that SLAB users with shrinkers will still get __GFP_RECLAIMABLE heuristic and so they will be placed properly for memory fragmentation prevention. I can see reasons we might want some gfp flag to reflect shorterm allocations but I propose starting from a clear semantic definition and only then add users with proper justification. This was been brought up before LSF this year by Matthew [1] and it turned out that GFP_TEMPORARY really doesn't have a clear semantic. It seems to be a heuristic without any measured advantage for most (if not all) its current users. The follow up discussion has revealed that opinions on what might be temporary allocation differ a lot between developers. So rather than trying to tweak existing users into a semantic which they haven't expected I propose to simply remove the flag and start from scratch if we really need a semantic for short term allocations. [1] http://lkml.kernel.org/r/20170118054945.GD18349@bombadil.infradead.org [akpm@linux-foundation.org: fix typo] [akpm@linux-foundation.org: coding-style fixes] [sfr@canb.auug.org.au: drm/i915: fix up] Link: http://lkml.kernel.org/r/20170816144703.378d4f4d@canb.auug.org.au Link: http://lkml.kernel.org/r/20170728091904.14627-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Matthew Wilcox <willy@infradead.org> Cc: Neil Brown <neilb@suse.de> Cc: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-13Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds5-3/+25
Pull scheduler fixes from Ingo Molnar: "Three CPU hotplug related fixes and a debugging improvement" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/debug: Add debugfs knob for "sched_debug" sched/core: WARN() when migrating to an offline CPU sched/fair: Plug hole between hotplug and active_load_balance() sched/fair: Avoid newidle balance for !active CPUs
2017-09-13Merge tag 'modules-for-v4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linuxLinus Torvalds1-6/+6
Pull modules updates from Jessica Yu: "Summary of modules changes for the 4.14 merge window: - minor code cleanups and fixes - modpost: avoid building modules that have names that exceed the size of the name field in struct module" * tag 'modules-for-v4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux: module: Remove const attribute from alias for MODULE_DEVICE_TABLE module: fix ddebug_remove_module() modpost: abort if module name is too long
2017-09-12Merge tag 'selinux-pr-20170831' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinuxLinus Torvalds1-4/+0
Pull selinux updates from Paul Moore: "A relatively quiet period for SELinux, 11 patches with only two/three having any substantive changes. These noteworthy changes include another tweak to the NNP/nosuid handling, per-file labeling for cgroups, and an object class fix for AF_UNIX/SOCK_RAW sockets; the rest of the changes are minor tweaks or administrative updates (Stephen's email update explains the file explosion in the diffstat). Everything passes the selinux-testsuite" [ Also a couple of small patches from the security tree from Tetsuo Handa for Tomoyo and LSM cleanup. The separation of security policy updates wasn't all that clean - Linus ] * tag 'selinux-pr-20170831' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux: selinux: constify nf_hook_ops selinux: allow per-file labeling for cgroupfs lsm_audit: update my email address selinux: update my email address MAINTAINERS: update the NetLabel and Labeled Networking information selinux: use GFP_NOWAIT in the AVC kmem_caches selinux: Generalize support for NNP/nosuid SELinux domain transitions selinux: genheaders should fail if too many permissions are defined selinux: update the selinux info in MAINTAINERS credits: update Paul Moore's info selinux: Assign proper class to PF_UNIX/SOCK_RAW sockets tomoyo: Update URLs in Documentation/admin-guide/LSM/tomoyo.rst LSM: Remove security_task_create() hook.
2017-09-12Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds4-8/+24
Pull scheduler fixes from Ingo Molnar: "Three fixes: - fix a suspend/resume cpusets bug - fix a !CONFIG_NUMA_BALANCING bug - fix a kerneldoc warning" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/fair: Fix nuisance kernel-doc warning sched/cpuset/pm: Fix cpuset vs. suspend-resume bugs sched/fair: Fix wake_affine_llc() balancing rules
2017-09-12Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds2-19/+10
Pull irq fixes from Ingo Molnar: "A sparse irq race/locking fix, and a MSI irq domains population fix" * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: genirq: Make sparse_irq_lock protect what it should protect genirq/msi: Fix populating multiple interrupts