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2020-07-17timer: Fix wheel index calculation on last levelFrederic Weisbecker1-2/+2
When an expiration delta falls into the last level of the wheel, that delta has be compared against the maximum possible delay and reduced to fit in if necessary. However instead of comparing the delta against the maximum, the code compares the actual expiry against the maximum. Then instead of fixing the delta to fit in, it sets the maximum delta as the expiry value. This can result in various undesired outcomes, the worst possible one being a timer expiring 15 days ahead to fire immediately. Fixes: 500462a9de65 ("timers: Switch to a non-cascading wheel") Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20200717140551.29076-2-frederic@kernel.org
2020-07-09timer: Prevent base->clk from moving backwardFrederic Weisbecker1-3/+14
When a timer is enqueued with a negative delta (ie: expiry is below base->clk), it gets added to the wheel as expiring now (base->clk). Yet the value that gets stored in base->next_expiry, while calling trigger_dyntick_cpu(), is the initial timer->expires value. The resulting state becomes: base->next_expiry < base->clk On the next timer enqueue, forward_timer_base() may accidentally rewind base->clk. As a possible outcome, timers may expire way too early, the worst case being that the highest wheel levels get spuriously processed again. To prevent from that, make sure that base->next_expiry doesn't get below base->clk. Fixes: a683f390b93f ("timers: Forward the wheel clock whenever possible") Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Anna-Maria Behnsen <anna-maria@linutronix.de> Tested-by: Juri Lelli <juri.lelli@redhat.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20200703010657.2302-1-frederic@kernel.org
2020-06-13Merge tag 'x86-entry-2020-06-12' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 entry updates from Thomas Gleixner: "The x86 entry, exception and interrupt code rework This all started about 6 month ago with the attempt to move the Posix CPU timer heavy lifting out of the timer interrupt code and just have lockless quick checks in that code path. Trivial 5 patches. This unearthed an inconsistency in the KVM handling of task work and the review requested to move all of this into generic code so other architectures can share. Valid request and solved with another 25 patches but those unearthed inconsistencies vs. RCU and instrumentation. Digging into this made it obvious that there are quite some inconsistencies vs. instrumentation in general. The int3 text poke handling in particular was completely unprotected and with the batched update of trace events even more likely to expose to endless int3 recursion. In parallel the RCU implications of instrumenting fragile entry code came up in several discussions. The conclusion of the x86 maintainer team was to go all the way and make the protection against any form of instrumentation of fragile and dangerous code pathes enforcable and verifiable by tooling. A first batch of preparatory work hit mainline with commit d5f744f9a2ac ("Pull x86 entry code updates from Thomas Gleixner") That (almost) full solution introduced a new code section '.noinstr.text' into which all code which needs to be protected from instrumentation of all sorts goes into. Any call into instrumentable code out of this section has to be annotated. objtool has support to validate this. Kprobes now excludes this section fully which also prevents BPF from fiddling with it and all 'noinstr' annotated functions also keep ftrace off. The section, kprobes and objtool changes are already merged. The major changes coming with this are: - Preparatory cleanups - Annotating of relevant functions to move them into the noinstr.text section or enforcing inlining by marking them __always_inline so the compiler cannot misplace or instrument them. - Splitting and simplifying the idtentry macro maze so that it is now clearly separated into simple exception entries and the more interesting ones which use interrupt stacks and have the paranoid handling vs. CR3 and GS. - Move quite some of the low level ASM functionality into C code: - enter_from and exit to user space handling. The ASM code now calls into C after doing the really necessary ASM handling and the return path goes back out without bells and whistels in ASM. - exception entry/exit got the equivivalent treatment - move all IRQ tracepoints from ASM to C so they can be placed as appropriate which is especially important for the int3 recursion issue. - Consolidate the declaration and definition of entry points between 32 and 64 bit. They share a common header and macros now. - Remove the extra device interrupt entry maze and just use the regular exception entry code. - All ASM entry points except NMI are now generated from the shared header file and the corresponding macros in the 32 and 64 bit entry ASM. - The C code entry points are consolidated as well with the help of DEFINE_IDTENTRY*() macros. This allows to ensure at one central point that all corresponding entry points share the same semantics. The actual function body for most entry points is in an instrumentable and sane state. There are special macros for the more sensitive entry points, e.g. INT3 and of course the nasty paranoid #NMI, #MCE, #DB and #DF. They allow to put the whole entry instrumentation and RCU handling into safe places instead of the previous pray that it is correct approach. - The INT3 text poke handling is now completely isolated and the recursion issue banned. Aside of the entry rework this required other isolation work, e.g. the ability to force inline bsearch. - Prevent #DB on fragile entry code, entry relevant memory and disable it on NMI, #MC entry, which allowed to get rid of the nested #DB IST stack shifting hackery. - A few other cleanups and enhancements which have been made possible through this and already merged changes, e.g. consolidating and further restricting the IDT code so the IDT table becomes RO after init which removes yet another popular attack vector - About 680 lines of ASM maze are gone. There are a few open issues: - An escape out of the noinstr section in the MCE handler which needs some more thought but under the aspect that MCE is a complete trainwreck by design and the propability to survive it is low, this was not high on the priority list. - Paravirtualization When PV is enabled then objtool complains about a bunch of indirect calls out of the noinstr section. There are a few straight forward ways to fix this, but the other issues vs. general correctness were more pressing than parawitz. - KVM KVM is inconsistent as well. Patches have been posted, but they have not yet been commented on or picked up by the KVM folks. - IDLE Pretty much the same problems can be found in the low level idle code especially the parts where RCU stopped watching. This was beyond the scope of the more obvious and exposable problems and is on the todo list. The lesson learned from this brain melting exercise to morph the evolved code base into something which can be validated and understood is that once again the violation of the most important engineering principle "correctness first" has caused quite a few people to spend valuable time on problems which could have been avoided in the first place. The "features first" tinkering mindset really has to stop. With that I want to say thanks to everyone involved in contributing to this effort. Special thanks go to the following people (alphabetical order): Alexandre Chartre, Andy Lutomirski, Borislav Petkov, Brian Gerst, Frederic Weisbecker, Josh Poimboeuf, Juergen Gross, Lai Jiangshan, Macro Elver, Paolo Bonzin,i Paul McKenney, Peter Zijlstra, Vitaly Kuznetsov, and Will Deacon" * tag 'x86-entry-2020-06-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (142 commits) x86/entry: Force rcu_irq_enter() when in idle task x86/entry: Make NMI use IDTENTRY_RAW x86/entry: Treat BUG/WARN as NMI-like entries x86/entry: Unbreak __irqentry_text_start/end magic x86/entry: __always_inline CR2 for noinstr lockdep: __always_inline more for noinstr x86/entry: Re-order #DB handler to avoid *SAN instrumentation x86/entry: __always_inline arch_atomic_* for noinstr x86/entry: __always_inline irqflags for noinstr x86/entry: __always_inline debugreg for noinstr x86/idt: Consolidate idt functionality x86/idt: Cleanup trap_init() x86/idt: Use proper constants for table size x86/idt: Add comments about early #PF handling x86/idt: Mark init only functions __init x86/entry: Rename trace_hardirqs_off_prepare() x86/entry: Clarify irq_{enter,exit}_rcu() x86/entry: Remove DBn stacks x86/entry: Remove debug IDT frobbing x86/entry: Optimize local_db_save() for virt ...
2020-06-12Merge tag 'x86-urgent-2020-06-11' of ↵Linus Torvalds1-2/+0
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull more x86 updates from Thomas Gleixner: "A set of fixes and updates for x86: - Unbreak paravirt VDSO clocks. While the VDSO code was moved into lib for sharing a subtle check for the validity of paravirt clocks got replaced. While the replacement works perfectly fine for bare metal as the update of the VDSO clock mode is synchronous, it fails for paravirt clocks because the hypervisor can invalidate them asynchronously. Bring it back as an optional function so it does not inflict this on architectures which are free of PV damage. - Fix the jiffies to jiffies64 mapping on 64bit so it does not trigger an ODR violation on newer compilers - Three fixes for the SSBD and *IB* speculation mitigation maze to ensure consistency, not disabling of some *IB* variants wrongly and to prevent a rogue cross process shutdown of SSBD. All marked for stable. - Add yet more CPU models to the splitlock detection capable list !@#%$! - Bring the pr_info() back which tells that TSC deadline timer is enabled. - Reboot quirk for MacBook6,1" * tag 'x86-urgent-2020-06-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/vdso: Unbreak paravirt VDSO clocks lib/vdso: Provide sanity check for cycles (again) clocksource: Remove obsolete ifdef x86_64: Fix jiffies ODR violation x86/speculation: PR_SPEC_FORCE_DISABLE enforcement for indirect branches. x86/speculation: Prevent rogue cross-process SSBD shutdown x86/speculation: Avoid force-disabling IBPB based on STIBP and enhanced IBRS. x86/cpu: Add Sapphire Rapids CPU model number x86/split_lock: Add Icelake microserver and Tigerlake CPU models x86/apic: Make TSC deadline timer detection message visible x86/reboot/quirks: Add MacBook6,1 reboot quirk
2020-06-11x86/mce: Address objtools noinstr complaintsThomas Gleixner1-1/+1
Mark the relevant functions noinstr, use the plain non-instrumented MSR accessors. The only odd part is the instrumentation_begin()/end() pair around the indirect machine_check_vector() call as objtool can't figure that out. The possible invoked functions are annotated correctly. Also use notrace variant of nmi_enter/exit(). If MCEs happen then hardware latency tracing is the least of the worries. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Andy Lutomirski <luto@kernel.org> Link: https://lkml.kernel.org/r/20200505135315.476734898@linutronix.de
2020-06-09clocksource: Remove obsolete ifdefThomas Gleixner1-2/+0
CONFIG_GENERIC_VDSO_CLOCK_MODE was a transitional config switch which got removed after all architectures got converted to the new storage model. But the removal forgot to remove the #ifdef which guards the vdso_clock_mode sanity check, which effectively disables the sanity check. Remove it now. Fixes: f86fd32db706 ("lib/vdso: Cleanup clock mode storage leftovers") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Miklos Szeredi <mszeredi@redhat.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20200606221531.845475036@linutronix.de
2020-06-04Merge branch 'proc-linus' of ↵Linus Torvalds1-64/+47
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull proc updates from Eric Biederman: "This has four sets of changes: - modernize proc to support multiple private instances - ensure we see the exit of each process tid exactly - remove has_group_leader_pid - use pids not tasks in posix-cpu-timers lookup Alexey updated proc so each mount of proc uses a new superblock. This allows people to actually use mount options with proc with no fear of messing up another mount of proc. Given the kernel's internal mounts of proc for things like uml this was a real problem, and resulted in Android's hidepid mount options being ignored and introducing security issues. The rest of the changes are small cleanups and fixes that came out of my work to allow this change to proc. In essence it is swapping the pids in de_thread during exec which removes a special case the code had to handle. Then updating the code to stop handling that special case" * 'proc-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: proc: proc_pid_ns takes super_block as an argument remove the no longer needed pid_alive() check in __task_pid_nr_ns() posix-cpu-timers: Replace __get_task_for_clock with pid_for_clock posix-cpu-timers: Replace cpu_timer_pid_type with clock_pid_type posix-cpu-timers: Extend rcu_read_lock removing task_struct references signal: Remove has_group_leader_pid exec: Remove BUG_ON(has_group_leader_pid) posix-cpu-timer: Unify the now redundant code in lookup_task posix-cpu-timer: Tidy up group_leader logic in lookup_task proc: Ensure we see the exit of each process tid exactly once rculist: Add hlists_swap_heads_rcu proc: Use PIDTYPE_TGID in next_tgid Use proc_pid_ns() to get pid_namespace from the proc superblock proc: use named enums for better readability proc: use human-readable values for hidepid docs: proc: add documentation for "hidepid=4" and "subset=pid" options and new mount behavior proc: add option to mount only a pids subset proc: instantiate only pids that we can ptrace on 'hidepid=4' mount option proc: allow to mount many instances of proc in one pid namespace proc: rename struct proc_fs_info to proc_fs_opts
2020-06-04Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextLinus Torvalds1-2/+1
Pull networking updates from David Miller: 1) Allow setting bluetooth L2CAP modes via socket option, from Luiz Augusto von Dentz. 2) Add GSO partial support to igc, from Sasha Neftin. 3) Several cleanups and improvements to r8169 from Heiner Kallweit. 4) Add IF_OPER_TESTING link state and use it when ethtool triggers a device self-test. From Andrew Lunn. 5) Start moving away from custom driver versions, use the globally defined kernel version instead, from Leon Romanovsky. 6) Support GRO vis gro_cells in DSA layer, from Alexander Lobakin. 7) Allow hard IRQ deferral during NAPI, from Eric Dumazet. 8) Add sriov and vf support to hinic, from Luo bin. 9) Support Media Redundancy Protocol (MRP) in the bridging code, from Horatiu Vultur. 10) Support netmap in the nft_nat code, from Pablo Neira Ayuso. 11) Allow UDPv6 encapsulation of ESP in the ipsec code, from Sabrina Dubroca. Also add ipv6 support for espintcp. 12) Lots of ReST conversions of the networking documentation, from Mauro Carvalho Chehab. 13) Support configuration of ethtool rxnfc flows in bcmgenet driver, from Doug Berger. 14) Allow to dump cgroup id and filter by it in inet_diag code, from Dmitry Yakunin. 15) Add infrastructure to export netlink attribute policies to userspace, from Johannes Berg. 16) Several optimizations to sch_fq scheduler, from Eric Dumazet. 17) Fallback to the default qdisc if qdisc init fails because otherwise a packet scheduler init failure will make a device inoperative. From Jesper Dangaard Brouer. 18) Several RISCV bpf jit optimizations, from Luke Nelson. 19) Correct the return type of the ->ndo_start_xmit() method in several drivers, it's netdev_tx_t but many drivers were using 'int'. From Yunjian Wang. 20) Add an ethtool interface for PHY master/slave config, from Oleksij Rempel. 21) Add BPF iterators, from Yonghang Song. 22) Add cable test infrastructure, including ethool interfaces, from Andrew Lunn. Marvell PHY driver is the first to support this facility. 23) Remove zero-length arrays all over, from Gustavo A. R. Silva. 24) Calculate and maintain an explicit frame size in XDP, from Jesper Dangaard Brouer. 25) Add CAP_BPF, from Alexei Starovoitov. 26) Support terse dumps in the packet scheduler, from Vlad Buslov. 27) Support XDP_TX bulking in dpaa2 driver, from Ioana Ciornei. 28) Add devm_register_netdev(), from Bartosz Golaszewski. 29) Minimize qdisc resets, from Cong Wang. 30) Get rid of kernel_getsockopt and kernel_setsockopt in order to eliminate set_fs/get_fs calls. From Christoph Hellwig. * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2517 commits) selftests: net: ip_defrag: ignore EPERM net_failover: fixed rollback in net_failover_open() Revert "tipc: Fix potential tipc_aead refcnt leak in tipc_crypto_rcv" Revert "tipc: Fix potential tipc_node refcnt leak in tipc_rcv" vmxnet3: allow rx flow hash ops only when rss is enabled hinic: add set_channels ethtool_ops support selftests/bpf: Add a default $(CXX) value tools/bpf: Don't use $(COMPILE.c) bpf, selftests: Use bpf_probe_read_kernel s390/bpf: Use bcr 0,%0 as tail call nop filler s390/bpf: Maintain 8-byte stack alignment selftests/bpf: Fix verifier test selftests/bpf: Fix sample_cnt shared between two threads bpf, selftests: Adapt cls_redirect to call csum_level helper bpf: Add csum_level helper for fixing up csum levels bpf: Fix up bpf_skb_adjust_room helper's skb csum setting sfc: add missing annotation for efx_ef10_try_update_nic_stats_vf() crypto/chtls: IPv6 support for inline TLS Crypto/chcr: Fixes a coccinile check error Crypto/chcr: Fixes compilations warnings ...
2020-05-09nsproxy: add struct nssetChristian Brauner1-2/+3
Add a simple struct nsset. It holds all necessary pieces to switch to a new set of namespaces without leaving a task in a half-switched state which we will make use of in the next patch. This patch switches the existing setns logic over without causing a change in setns() behavior. This brings setns() closer to how unshare() works(). The prepare_ns() function is responsible to prepare all necessary information. This has two reasons. First it minimizes dependencies between individual namespaces, i.e. all install handler can expect that all fields are properly initialized independent in what order they are called in. Second, this makes the code easier to maintain and easier to follow if it needs to be changed. The prepare_ns() helper will only be switched over to use a flags argument in the next patch. Here it will still use nstype as a simple integer argument which was argued would be clearer. I'm not particularly opinionated about this if it really helps or not. The struct nsset itself already contains the flags field since its name already indicates that it can contain information required by different namespaces. None of this should have functional consequences. Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Serge Hallyn <serge@hallyn.com> Cc: Jann Horn <jannh@google.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Aleksa Sarai <cyphar@cyphar.com> Link: https://lore.kernel.org/r/20200505140432.181565-2-christian.brauner@ubuntu.com
2020-04-29posix-cpu-timers: Replace __get_task_for_clock with pid_for_clockEric W. Biederman1-45/+30
Now that the codes store references to pids instead of referendes to tasks. Looking up a task for a clock instead of looking up a struct pid makes the code more difficult to verify it is correct than necessary. In posix_cpu_timers_create get_task_pid can race with release_task for threads and return a NULL pid. As put_pid and cpu_timer_task_rcu handle NULL pids just fine the code works without problems but it is an extra case to consider and keep in mind while verifying and modifying the code. There are races with de_thread to consider that only don't apply because thread clocks are only allowed for threads in the same thread_group. So instead of leaving a burden for people making modification to the code in the future return a rcu protected struct pid for the clock instead. The logic for __get_task_for_pid and lookup_task has been folded into the new function pid_for_clock with the only change being the logic has been modified from working on a task to working on a pid that will be returned. In posix_cpu_clock_get instead of calling pid_for_clock checking the result and then calling pid_task to get the task. The result of pid_for_clock is fed directly into pid_task. This is safe because pid_task handles NULL pids. As such an extra error check was unnecessary. Instead of hiding the flag that enables the special clock_gettime handling, I have made the 3 callers just pass the flag in themselves. That is less code and seems just as simple to work with as the wrapper functions. Historically the clock_gettime special case of allowing a process clock to be found by the thread id did not even exist [33ab0fec3352] but Thomas Gleixner reports that he has found code that uses that functionality [55e8c8eb2c7b]. Link: https://lkml.kernel.org/r/87zhaxqkwa.fsf@nanos.tec.linutronix.de/ Ref: 33ab0fec3352 ("posix-timers: Consolidate posix_cpu_clock_get()") Ref: 55e8c8eb2c7b ("posix-cpu-timers: Store a reference to a pid not a task") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-04-29posix-cpu-timers: Replace cpu_timer_pid_type with clock_pid_typeEric W. Biederman1-4/+4
Taking a clock and returning a pid_type is a more general and a superset of taking a timer and returning a pid_type. Perform this generalization so that future changes may use this code on clocks as well as timers. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-04-29posix-cpu-timers: Extend rcu_read_lock removing task_struct referencesEric W. Biederman1-20/+23
Now that the code stores of pid references it is no longer necessary or desirable to take a reference on task_struct in __get_task_for_clock. Instead extend the scope of rcu_read_lock and remove the reference counting on struct task_struct entirely. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-04-29posix-cpu-timer: Unify the now redundant code in lookup_taskEric W. Biederman1-8/+7
Now that both !thread paths through lookup_task call thread_group_leader, unify them into the single test at the end of lookup_task. This unification just makes it clear what is happening in the gettime special case of lookup_task. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-04-29posix-cpu-timer: Tidy up group_leader logic in lookup_taskEric W. Biederman1-6/+2
Replace has_group_leader_pid with thread_group_leader. Years ago Oleg suggested changing thread_group_leader to has_group_leader_pid to handle races. Looking at the code then and now I don't see how it ever helped. Especially as then the code really did need to be the thread_group_leader. Today it doesn't make a difference if thread_group_leader races with de_thread as the task returned from lookup_task in the non-thread case is just used to find values in task->signal. Since the races with de_thread have never been handled revert has_group_header_pid to thread_group_leader for clarity. Update the comment in lookup_task to remove implementation details that are no longer true and to mention task->signal instead of task->sighand, as the relevant cpu timer details are all in task->signal. Ref: 55e8c8eb2c7b ("posix-cpu-timers: Store a reference to a pid not a task") Ref: c0deae8c9587 ("posix-cpu-timers: Rcu_read_lock/unlock protect find_task_by_vpid call") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-04-28Merge branch 'work.sysctl' of ↵Daniel Borkmann1-2/+1
ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull in Christoph Hellwig's series that changes the sysctl's ->proc_handler methods to take kernel pointers instead. It gets rid of the set_fs address space overrides used by BPF. As per discussion, pull in the feature branch into bpf-next as it relates to BPF sysctl progs. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200427071508.GV23230@ZenIV.linux.org.uk/T/
2020-04-27sysctl: pass kernel pointers to ->proc_handlerChristoph Hellwig1-2/+1
Instead of having all the sysctl handlers deal with user pointers, which is rather hairy in terms of the BPF interaction, copy the input to and from userspace in common code. This also means that the strings are always NUL-terminated by the common code, making the API a little bit safer. As most handler just pass through the data to one of the common handlers a lot of the changes are mechnical. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-04-16proc, time/namespace: Show clock symbolic names in /proc/pid/timens_offsetsAndrei Vagin1-1/+14
Michael Kerrisk suggested to replace numeric clock IDs with symbolic names. Now the content of these files looks like this: $ cat /proc/774/timens_offsets monotonic 864000 0 boottime 1728000 0 For setting offsets, both representations of clocks (numeric and symbolic) can be used. As for compatibility, it is acceptable to change things as long as userspace doesn't care. The format of timens_offsets files is very new and there are no userspace tools yet which rely on this format. But three projects crun, util-linux and criu rely on the interface of setting time offsets and this is why it's required to continue supporting the numeric clock IDs on write. Fixes: 04a8682a71be ("fs/proc: Introduce /proc/pid/timens_offsets") Suggested-by: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: Andrei Vagin <avagin@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Dmitry Safonov <0x7f454c46@gmail.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20200411154031.642557-1-avagin@gmail.com
2020-04-07time/namespace: Fix time_for_children symlinkMichael Kerrisk (man-pages)1-0/+1
Looking at the contents of the /proc/PID/ns/time_for_children symlink shows an anomaly: $ ls -l /proc/self/ns/* |awk '{print $9, $10, $11}' ... /proc/self/ns/pid -> pid:[4026531836] /proc/self/ns/pid_for_children -> pid:[4026531836] /proc/self/ns/time -> time:[4026531834] /proc/self/ns/time_for_children -> time_for_children:[4026531834] /proc/self/ns/user -> user:[4026531837] ... The reference for 'time_for_children' should be a 'time' namespace, just as the reference for 'pid_for_children' is a 'pid' namespace. In other words, the above time_for_children link should read: /proc/self/ns/time_for_children -> time:[4026531834] Fixes: 769071ac9f20 ("ns: Introduce Time Namespace") Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Dmitry Safonov <dima@arista.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Acked-by: Andrei Vagin <avagin@gmail.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/a2418c48-ed80-3afe-116e-6611cb799557@gmail.com
2020-04-01hrtimer: Don't dereference the hrtimer pointer after the callbackSebastian Andrzej Siewior1-2/+3
A hrtimer can be released in its callback, but lockdep_hrtimer_exit() dereferences the pointer after the callback returns, i.e. a potential use after free. Retrieve the context in which the hrtimer expires before the callback is invoked and use it in lockdep_hrtimer_exit(). Fixes: 40db173965c0 ("lockdep: Add hrtimer context tracing bits") Reported-by: syzbot+62c155c276e580cfb606@syzkaller.appspotmail.com Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200331201849.fkp2siy3vcdqvqlz@linutronix.de
2020-03-31Merge tag 'timers-core-2020-03-30' of ↵Linus Torvalds9-101/+108
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timekeeping and timer updates from Thomas Gleixner: "Core: - Consolidation of the vDSO build infrastructure to address the difficulties of cross-builds for ARM64 compat vDSO libraries by restricting the exposure of header content to the vDSO build. This is achieved by splitting out header content into separate headers. which contain only the minimaly required information which is necessary to build the vDSO. These new headers are included from the kernel headers and the vDSO specific files. - Enhancements to the generic vDSO library allowing more fine grained control over the compiled in code, further reducing architecture specific storage and preparing for adopting the generic library by PPC. - Cleanup and consolidation of the exit related code in posix CPU timers. - Small cleanups and enhancements here and there Drivers: - The obligatory new drivers: Ingenic JZ47xx and X1000 TCU support - Correct the clock rate of PIT64b global clock - setup_irq() cleanup - Preparation for PWM and suspend support for the TI DM timer - Expand the fttmr010 driver to support ast2600 systems - The usual small fixes, enhancements and cleanups all over the place" * tag 'timers-core-2020-03-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (80 commits) Revert "clocksource/drivers/timer-probe: Avoid creating dead devices" vdso: Fix clocksource.h macro detection um: Fix header inclusion arm64: vdso32: Enable Clang Compilation lib/vdso: Enable common headers arm: vdso: Enable arm to use common headers x86/vdso: Enable x86 to use common headers mips: vdso: Enable mips to use common headers arm64: vdso32: Include common headers in the vdso library arm64: vdso: Include common headers in the vdso library arm64: Introduce asm/vdso/processor.h arm64: vdso32: Code clean up linux/elfnote.h: Replace elf.h with UAPI equivalent scripts: Fix the inclusion order in modpost common: Introduce processor.h linux/ktime.h: Extract common header for vDSO linux/jiffies.h: Extract common header for vDSO linux/time64.h: Extract common header for vDSO linux/time32.h: Extract common header for vDSO linux/time.h: Extract common header for vDSO ...
2020-03-31Merge branch 'locking-core-for-linus' of ↵Linus Torvalds7-19/+39
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking updates from Ingo Molnar: "The main changes in this cycle were: - Continued user-access cleanups in the futex code. - percpu-rwsem rewrite that uses its own waitqueue and atomic_t instead of an embedded rwsem. This addresses a couple of weaknesses, but the primary motivation was complications on the -rt kernel. - Introduce raw lock nesting detection on lockdep (CONFIG_PROVE_RAW_LOCK_NESTING=y), document the raw_lock vs. normal lock differences. This too originates from -rt. - Reuse lockdep zapped chain_hlocks entries, to conserve RAM footprint on distro-ish kernels running into the "BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!" depletion of the lockdep chain-entries pool. - Misc cleanups, smaller fixes and enhancements - see the changelog for details" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (55 commits) fs/buffer: Make BH_Uptodate_Lock bit_spin_lock a regular spinlock_t thermal/x86_pkg_temp: Make pkg_temp_lock a raw_spinlock_t Documentation/locking/locktypes: Minor copy editor fixes Documentation/locking/locktypes: Further clarifications and wordsmithing m68knommu: Remove mm.h include from uaccess_no.h x86: get rid of user_atomic_cmpxchg_inatomic() generic arch_futex_atomic_op_inuser() doesn't need access_ok() x86: don't reload after cmpxchg in unsafe_atomic_op2() loop x86: convert arch_futex_atomic_op_inuser() to user_access_begin/user_access_end() objtool: whitelist __sanitizer_cov_trace_switch() [parisc, s390, sparc64] no need for access_ok() in futex handling sh: no need of access_ok() in arch_futex_atomic_op_inuser() futex: arch_futex_atomic_op_inuser() calling conventions change completion: Use lockdep_assert_RT_in_threaded_ctx() in complete_all() lockdep: Add posixtimer context tracing bits lockdep: Annotate irq_work lockdep: Add hrtimer context tracing bits lockdep: Introduce wait-type checks completion: Use simple wait queues sched/swait: Prepare usage in completions ...
2020-03-24Merge branch 'for-mingo' of ↵Ingo Molnar1-3/+4
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu Pull RCU changes from Paul E. McKenney: - Make kfree_rcu() use kfree_bulk() for added performance - RCU updates - Callback-overload handling updates - Tasks-RCU KCSAN and sparse updates - Locking torture test and RCU torture test updates - Documentation updates - Miscellaneous fixes Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-03-21lockdep: Add posixtimer context tracing bitsSebastian Andrzej Siewior1-1/+5
Splitting run_posix_cpu_timers() into two parts is work in progress which is stuck on other entry code related problems. The heavy lifting which involves locking of sighand lock will be moved into task context so the necessary execution time is burdened on the task and not on interrupt context. Until this work completes lockdep with the spinlock nesting rules enabled would emit warnings for this known context. Prevent it by setting "->irq_config = 1" for the invocation of run_posix_cpu_timers() so lockdep does not complain when sighand lock is acquried. This will be removed once the split is completed. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200321113242.751182723@linutronix.de
2020-03-21lockdep: Annotate irq_workSebastian Andrzej Siewior1-0/+1
Mark irq_work items with IRQ_WORK_HARD_IRQ which should be invoked in hardirq context even on PREEMPT_RT. IRQ_WORK without this flag will be invoked in softirq context on PREEMPT_RT. Set ->irq_config to 1 for the IRQ_WORK items which are invoked in softirq context so lockdep knows that these can safely acquire a spinlock_t. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200321113242.643576700@linutronix.de
2020-03-21lockdep: Add hrtimer context tracing bitsSebastian Andrzej Siewior1-1/+5
Set current->irq_config = 1 for hrtimers which are not marked to expire in hard interrupt context during hrtimer_init(). These timers will expire in softirq context on PREEMPT_RT. Setting this allows lockdep to differentiate these timers. If a timer is marked to expire in hard interrupt context then the timer callback is not supposed to acquire a regular spinlock instead of a raw_spinlock in the expiry callback. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200321113242.534508206@linutronix.de
2020-03-21timekeeping: Split jiffies seqlockThomas Gleixner5-17/+28
seqlock consists of a sequence counter and a spinlock_t which is used to serialize the writers. spinlock_t is substituted by a "sleeping" spinlock on PREEMPT_RT enabled kernels which breaks the usage in the timekeeping code as the writers are executed in hard interrupt and therefore non-preemptible context even on PREEMPT_RT. The spinlock in seqlock cannot be unconditionally replaced by a raw_spinlock_t as many seqlock users have nesting spinlock sections or other code which is not suitable to run in truly atomic context on RT. Instead of providing a raw_seqlock API for a single use case, open code the seqlock for the jiffies use case and implement it with a raw_spinlock_t and a sequence counter. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200321113242.120587764@linutronix.de
2020-03-19Revert "tick/common: Make tick_periodic() check for missing ticks"Thomas Gleixner1-33/+3
This reverts commit d441dceb5dce71150f28add80d36d91bbfccba99 due to boot failures. Reported-by: Qian Cai <cai@lca.pw> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com>
2020-03-19time/sched_clock: Expire timer in hardirq contextAhmed S. Darwish1-4/+5
To minimize latency, PREEMPT_RT kernels expires hrtimers in preemptible softirq context by default. This can be overriden by marking the timer's expiry with HRTIMER_MODE_HARD. sched_clock_timer is missing this annotation: if its callback is preempted and the duration of the preemption exceeds the wrap around time of the underlying clocksource, sched clock will get out of sync. Mark the sched_clock_timer for expiry in hard interrupt context. Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200309181529.26558-1-a.darwish@linutronix.de
2020-03-04tick/common: Make tick_periodic() check for missing ticksWaiman Long1-3/+33
The tick_periodic() function is used at the beginning part of the bootup process for time keeping while the other clock sources are being initialized. The current code assumes that all the timer interrupts are handled in a timely manner with no missing ticks. That is not actually true. Some ticks are missed and there are some discrepancies between the tick time (jiffies) and the timestamp reported in the kernel log. Some systems, however, are more prone to missing ticks than the others. In the extreme case, the discrepancy can actually cause a soft lockup message to be printed by the watchdog kthread. For example, on a Cavium ThunderX2 Sabre arm64 system: [ 25.496379] watchdog: BUG: soft lockup - CPU#14 stuck for 22s! On that system, the missing ticks are especially prevalent during the smp_init() phase of the boot process. With an instrumented kernel, it was found that it took about 24s as reported by the timestamp for the tick to accumulate 4s of time. Investigation and bisection done by others seemed to point to the commit 73f381660959 ("arm64: Advertise mitigation of Spectre-v2, or lack thereof") as the culprit. It could also be a firmware issue as new firmware was promised that would fix the issue. To properly address this problem, stop assuming that there will be no missing tick in tick_periodic(). Modify it to follow the example of tick_do_update_jiffies64() by using another reference clock to check for missing ticks. Since the watchdog timer uses running_clock(), it is used here as the reference. With this applied, the soft lockup problem in the affected arm64 system is gone and tick time tracks much more closely to the timestamp time. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200207193929.27308-1-longman@redhat.com
2020-03-04hrtimer: Cast explicitely to u32t in __ktime_divns()Wen Yang1-1/+1
do_div() does a 64-by-32 division at least on 32bit platforms, while the divisor 'div' is explicitly casted to unsigned long, thus 64-bit on 64-bit platforms. The code already ensures that the divisor is less than 2^32. Hence the proper cast type is u32. Signed-off-by: Wen Yang <wenyang@linux.alibaba.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200130130851.29204-1-wenyang@linux.alibaba.com
2020-03-04timekeeping: Prevent 32bit truncation in scale64_check_overflow()Wen Yang1-2/+1
While unlikely the divisor in scale64_check_overflow() could be >= 32bit in scale64_check_overflow(). do_div() truncates the divisor to 32bit at least on 32bit platforms. Use div64_u64() instead to avoid the truncation to 32-bit. [ tglx: Massaged changelog ] Signed-off-by: Wen Yang <wenyang@linux.alibaba.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200120100523.45656-1-wenyang@linux.alibaba.com
2020-03-04posix-cpu-timers: Store a reference to a pid not a taskEric W. Biederman1-18/+55
posix cpu timers do not handle the death of a process well. This is most clearly seen when a multi-threaded process calls exec from a thread that is not the leader of the thread group. The posix cpu timer code continues to pin the old thread group leader and is unable to find the siglock from there. This results in posix_cpu_timer_del being unable to delete a timer, posix_cpu_timer_set being unable to set a timer. Further to compensate for the problems in posix_cpu_timer_del on a multi-threaded exec all timers that point at the multi-threaded task are stopped. The code for the timers fundamentally needs to check if the target process/thread is alive. This needs an extra level of indirection. This level of indirection is already available in struct pid. So replace cpu.task with cpu.pid to get the needed extra layer of indirection. In addition to handling things more cleanly this reduces the amount of memory a timer can pin when a process exits and then is reaped from a task_struct to the vastly smaller struct pid. Fixes: e0a70217107e ("posix-cpu-timers: workaround to suppress the problems with mt exec") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/87wo86tz6d.fsf@x220.int.ebiederm.org
2020-03-01posix-cpu-timers: Pass the task into arm_timer()Eric W. Biederman1-4/+3
The task has been already computed to take siglock before calling arm_timer. So pass the benefit of that labor into arm_timer(). Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/8736auvdt1.fsf@x220.int.ebiederm.org
2020-03-01posix-cpu-timers: Remove unnecessary locking around cpu_clock_sample_groupEric W. Biederman1-54/+12
As of e78c3496790e ("time, signal: Protect resource use statistics with seqlock") cpu_clock_sample_group no longers needs siglock protection. Unfortunately no one realized it at the time. Remove the extra locking that is for cpu_clock_sample_group and not for cpu_clock_sample. This significantly simplifies the code. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/878skmvdts.fsf@x220.int.ebiederm.org
2020-03-01posix-cpu-timers: cpu_clock_sample_group() no longer needs siglockEric W. Biederman1-3/+1
As of e78c3496790e ("time, signal: Protect resource use statistics with seqlock") cpu_clock_sample_group() no longer needs siglock protection so remove the stale comment. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/87eeuevduq.fsf@x220.int.ebiederm.org
2020-02-21y2038: remove unused time32 interfacesArnd Bergmann1-43/+0
No users remain, so kill these off before we grow new ones. Link: http://lkml.kernel.org/r/20200110154232.4104492-3-arnd@arndb.de Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Deepa Dinamani <deepa.kernel@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-02-21timer: Use hlist_unhashed_lockless() in timer_pending()Eric Dumazet1-3/+4
The timer_pending() function is mostly used in lockless contexts, so Without proper annotations, KCSAN might detect a data-race [1]. Using hlist_unhashed_lockless() instead of hand-coding it seems appropriate (as suggested by Paul E. McKenney). [1] BUG: KCSAN: data-race in del_timer / detach_if_pending write to 0xffff88808697d870 of 8 bytes by task 10 on cpu 0: __hlist_del include/linux/list.h:764 [inline] detach_timer kernel/time/timer.c:815 [inline] detach_if_pending+0xcd/0x2d0 kernel/time/timer.c:832 try_to_del_timer_sync+0x60/0xb0 kernel/time/timer.c:1226 del_timer_sync+0x6b/0xa0 kernel/time/timer.c:1365 schedule_timeout+0x2d2/0x6e0 kernel/time/timer.c:1896 rcu_gp_fqs_loop+0x37c/0x580 kernel/rcu/tree.c:1639 rcu_gp_kthread+0x143/0x230 kernel/rcu/tree.c:1799 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352 read to 0xffff88808697d870 of 8 bytes by task 12060 on cpu 1: del_timer+0x3b/0xb0 kernel/time/timer.c:1198 sk_stop_timer+0x25/0x60 net/core/sock.c:2845 inet_csk_clear_xmit_timers+0x69/0xa0 net/ipv4/inet_connection_sock.c:523 tcp_clear_xmit_timers include/net/tcp.h:606 [inline] tcp_v4_destroy_sock+0xa3/0x3f0 net/ipv4/tcp_ipv4.c:2096 inet_csk_destroy_sock+0xf4/0x250 net/ipv4/inet_connection_sock.c:836 tcp_close+0x6f3/0x970 net/ipv4/tcp.c:2497 inet_release+0x86/0x100 net/ipv4/af_inet.c:427 __sock_release+0x85/0x160 net/socket.c:590 sock_close+0x24/0x30 net/socket.c:1268 __fput+0x1e1/0x520 fs/file_table.c:280 ____fput+0x1f/0x30 fs/file_table.c:313 task_work_run+0xf6/0x130 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x2b4/0x2c0 arch/x86/entry/common.c:163 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 12060 Comm: syz-executor.5 Not tainted 5.4.0-rc3+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> [ paulmck: Pulled in Eric's later amendments. ] Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-02-17posix-timers: Pass lockdep expression to RCU listsAmol Grover1-1/+2
head is traversed using hlist_for_each_entry_rcu outside an RCU read-side critical section but under the protection of hash_lock. Hence, add corresponding lockdep expression to silence false-positive lockdep warnings, and harden RCU lists. [ tglx: Removed the macro and put the condition right where it's used ] Signed-off-by: Amol Grover <frextrite@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200216074330.GA14025@workstation-portable
2020-02-17timer: Improve the comment describing schedule_timeout()Alexander Popov1-7/+9
When working commit 6dcd5d7a7a29c1e, a mistake was noticed by Linus: schedule_timeout() was called without setting the task state to anything particular. It calls the scheduler, but doesn't delay anything, because the task stays runnable. That happens because sched_submit_work() does nothing for tasks in TASK_RUNNING state. That turned out to be the intended behavior. Adding a WARN() is not useful as the task could be woken up right after setting the state and before reaching schedule_timeout(). Improve the comment about schedule_timeout() and describe that more explicitly. Signed-off-by: Alexander Popov <alex.popov@linux.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200117225900.16340-1-alex.popov@linux.com
2020-02-17lib/vdso: Move VCLOCK_TIMENS to vdso_clock_modesThomas Gleixner1-3/+4
Move the time namespace indicator clock mode to the other ones for consistency sake. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Link: https://lkml.kernel.org/r/20200207124403.656097274@linutronix.de
2020-02-17lib/vdso: Avoid highres update if clocksource is not VDSO capableThomas Gleixner1-3/+3
If the current clocksource is not VDSO capable there is no point in updating the high resolution parts of the VDSO data. Replace the architecture specific check with a check for a VDSO capable clocksource and skip the update if there is none. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Link: https://lkml.kernel.org/r/20200207124403.563379423@linutronix.de
2020-02-17lib/vdso: Cleanup clock mode storage leftoversThomas Gleixner1-4/+0
Now that all architectures are converted to use the generic storage the helpers and conditionals can be removed. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Link: https://lkml.kernel.org/r/20200207124403.470699892@linutronix.de
2020-02-17clocksource: Add common vdso clock mode storageThomas Gleixner2-2/+17
All architectures which use the generic VDSO code have their own storage for the VDSO clock mode. That's pointless and just requires duplicate code. Provide generic storage for it. The new Kconfig symbol is intermediate and will be removed once all architectures are converted over. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Link: https://lkml.kernel.org/r/20200207124403.028046322@linutronix.de
2020-02-09Merge tag 'timers-urgent-2020-02-09' of ↵Linus Torvalds1-2/+9
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fixes from Thomas Gleixner: "Two small fixes for the time(r) subsystem: - Handle a subtle race between the clocksource watchdog and a concurrent clocksource watchdog stop/start sequence correctly to prevent a timer double add bug. - Fix the file path for the core time namespace file" * tag 'timers-urgent-2020-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: clocksource: Prevent double add_timer_on() for watchdog_timer MAINTAINERS: Correct path to time namespace source file
2020-02-01clocksource: Prevent double add_timer_on() for watchdog_timerKonstantin Khlebnikov1-2/+9
Kernel crashes inside QEMU/KVM are observed: kernel BUG at kernel/time/timer.c:1154! BUG_ON(timer_pending(timer) || !timer->function) in add_timer_on(). At the same time another cpu got: general protection fault: 0000 [#1] SMP PTI of poinson pointer 0xdead000000000200 in: __hlist_del at include/linux/list.h:681 (inlined by) detach_timer at kernel/time/timer.c:818 (inlined by) expire_timers at kernel/time/timer.c:1355 (inlined by) __run_timers at kernel/time/timer.c:1686 (inlined by) run_timer_softirq at kernel/time/timer.c:1699 Unfortunately kernel logs are badly scrambled, stacktraces are lost. Printing the timer->function before the BUG_ON() pointed to clocksource_watchdog(). The execution of clocksource_watchdog() can race with a sequence of clocksource_stop_watchdog() .. clocksource_start_watchdog(): expire_timers() detach_timer(timer, true); timer->entry.pprev = NULL; raw_spin_unlock_irq(&base->lock); call_timer_fn clocksource_watchdog() clocksource_watchdog_kthread() or clocksource_unbind() spin_lock_irqsave(&watchdog_lock, flags); clocksource_stop_watchdog(); del_timer(&watchdog_timer); watchdog_running = 0; spin_unlock_irqrestore(&watchdog_lock, flags); spin_lock_irqsave(&watchdog_lock, flags); clocksource_start_watchdog(); add_timer_on(&watchdog_timer, ...); watchdog_running = 1; spin_unlock_irqrestore(&watchdog_lock, flags); spin_lock(&watchdog_lock); add_timer_on(&watchdog_timer, ...); BUG_ON(timer_pending(timer) || !timer->function); timer_pending() -> true BUG() I.e. inside clocksource_watchdog() watchdog_timer could be already armed. Check timer_pending() before calling add_timer_on(). This is sufficient as all operations are synchronized by watchdog_lock. Fixes: 75c5158f70c0 ("timekeeping: Update clocksource with stop_machine") Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/158048693917.4378.13823603769948933793.stgit@buzz
2020-01-30Merge tag 'y2038-drivers-for-v5.6-signed' of ↵Linus Torvalds2-62/+14
git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground Pull y2038 updates from Arnd Bergmann: "Core, driver and file system changes These are updates to device drivers and file systems that for some reason or another were not included in the kernel in the previous y2038 series. I've gone through all users of time_t again to make sure the kernel is in a long-term maintainable state, replacing all remaining references to time_t with safe alternatives. Some related parts of the series were picked up into the nfsd, xfs, alsa and v4l2 trees. A final set of patches in linux-mm removes the now unused time_t/timeval/timespec types and helper functions after all five branches are merged for linux-5.6, ensuring that no new users get merged. As a result, linux-5.6, or my backport of the patches to 5.4 [1], should be the first release that can serve as a base for a 32-bit system designed to run beyond year 2038, with a few remaining caveats: - All user space must be compiled with a 64-bit time_t, which will be supported in the coming musl-1.2 and glibc-2.32 releases, along with installed kernel headers from linux-5.6 or higher. - Applications that use the system call interfaces directly need to be ported to use the time64 syscalls added in linux-5.1 in place of the existing system calls. This impacts most users of futex() and seccomp() as well as programming languages that have their own runtime environment not based on libc. - Applications that use a private copy of kernel uapi header files or their contents may need to update to the linux-5.6 version, in particular for sound/asound.h, xfs/xfs_fs.h, linux/input.h, linux/elfcore.h, linux/sockios.h, linux/timex.h and linux/can/bcm.h. - A few remaining interfaces cannot be changed to pass a 64-bit time_t in a compatible way, so they must be configured to use CLOCK_MONOTONIC times or (with a y2106 problem) unsigned 32-bit timestamps. Most importantly this impacts all users of 'struct input_event'. - All y2038 problems that are present on 64-bit machines also apply to 32-bit machines. In particular this affects file systems with on-disk timestamps using signed 32-bit seconds: ext4 with ext3-style small inodes, ext2, xfs (to be fixed soon) and ufs" [1] https://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground.git/log/?h=y2038-endgame * tag 'y2038-drivers-for-v5.6-signed' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground: (21 commits) Revert "drm/etnaviv: reject timeouts with tv_nsec >= NSEC_PER_SEC" y2038: sh: remove timeval/timespec usage from headers y2038: sparc: remove use of struct timex y2038: rename itimerval to __kernel_old_itimerval y2038: remove obsolete jiffies conversion functions nfs: fscache: use timespec64 in inode auxdata nfs: fix timstamp debug prints nfs: use time64_t internally sunrpc: convert to time64_t for expiry drm/etnaviv: avoid deprecated timespec drm/etnaviv: reject timeouts with tv_nsec >= NSEC_PER_SEC drm/msm: avoid using 'timespec' hfs/hfsplus: use 64-bit inode timestamps hostfs: pass 64-bit timestamps to/from user space packet: clarify timestamp overflow tsacct: add 64-bit btime field acct: stop using get_seconds() um: ubd: use 64-bit time_t where possible xtensa: ISS: avoid struct timeval dlm: use SO_SNDTIMEO_NEW instead of SO_SNDTIMEO_OLD ...
2020-01-28Merge tag 'timers-core-2020-01-27' of ↵Linus Torvalds11-107/+656
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Thomas Gleixner: "The timekeeping and timers departement provides: - Time namespace support: If a container migrates from one host to another then it expects that clocks based on MONOTONIC and BOOTTIME are not subject to disruption. Due to different boot time and non-suspended runtime these clocks can differ significantly on two hosts, in the worst case time goes backwards which is a violation of the POSIX requirements. The time namespace addresses this problem. It allows to set offsets for clock MONOTONIC and BOOTTIME once after creation and before tasks are associated with the namespace. These offsets are taken into account by timers and timekeeping including the VDSO. Offsets for wall clock based clocks (REALTIME/TAI) are not provided by this mechanism. While in theory possible, the overhead and code complexity would be immense and not justified by the esoteric potential use cases which were discussed at Plumbers '18. The overhead for tasks in the root namespace (ie where host time offsets = 0) is in the noise and great effort was made to ensure that especially in the VDSO. If time namespace is disabled in the kernel configuration the code is compiled out. Kudos to Andrei Vagin and Dmitry Sofanov who implemented this feature and kept on for more than a year addressing review comments, finding better solutions. A pleasant experience. - Overhaul of the alarmtimer device dependency handling to ensure that the init/suspend/resume ordering is correct. - A new clocksource/event driver for Microchip PIT64 - Suspend/resume support for the Hyper-V clocksource - The usual pile of fixes, updates and improvements mostly in the driver code" * tag 'timers-core-2020-01-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (71 commits) alarmtimer: Make alarmtimer_get_rtcdev() a stub when CONFIG_RTC_CLASS=n alarmtimer: Use wakeup source from alarmtimer platform device alarmtimer: Make alarmtimer platform device child of RTC device alarmtimer: Update alarmtimer_get_rtcdev() docs to reflect reality hrtimer: Add missing sparse annotation for __run_timer() lib/vdso: Only read hrtimer_res when needed in __cvdso_clock_getres() MIPS: vdso: Define BUILD_VDSO32 when building a 32bit kernel clocksource/drivers/hyper-v: Set TSC clocksource as default w/ InvariantTSC clocksource/drivers/hyper-v: Untangle stimers and timesync from clocksources clocksource/drivers/timer-microchip-pit64b: Fix sparse warning clocksource/drivers/exynos_mct: Rename Exynos to lowercase clocksource/drivers/timer-ti-dm: Fix uninitialized pointer access clocksource/drivers/timer-ti-dm: Switch to platform_get_irq clocksource/drivers/timer-ti-dm: Convert to devm_platform_ioremap_resource clocksource/drivers/em_sti: Fix variable declaration in em_sti_probe clocksource/drivers/em_sti: Convert to devm_platform_ioremap_resource clocksource/drivers/bcm2835_timer: Fix memory leak of timer clocksource/drivers/cadence-ttc: Use ttc driver as platform driver clocksource/drivers/timer-microchip-pit64b: Add Microchip PIT64B support clocksource/drivers/hyper-v: Reserve PAGE_SIZE space for tsc page ...
2020-01-24alarmtimer: Make alarmtimer_get_rtcdev() a stub when CONFIG_RTC_CLASS=nStephen Boyd1-5/+0
The stubbed version of alarmtimer_get_rtcdev() is not exported. so this won't work if this function is used in a module when CONFIG_RTC_CLASS=n. Move the stub function to the header file and make it inline so that callers don't have to worry about linking against this symbol. rtcdev isn't used outside of this ifdef so it's not required to be redefined to NULL. Drop that while touching this area. Signed-off-by: Stephen Boyd <swboyd@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20200124055849.154411-4-swboyd@chromium.org
2020-01-24alarmtimer: Use wakeup source from alarmtimer platform deviceStephen Boyd1-10/+5
Use the wakeup source that can be associated with the 'alarmtimer' platform device instead of registering another one by hand. Signed-off-by: Stephen Boyd <swboyd@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20200124055849.154411-3-swboyd@chromium.org
2020-01-24alarmtimer: Make alarmtimer platform device child of RTC deviceStephen Boyd1-11/+9
The alarmtimer_suspend() function will fail if an RTC device is on a bus such as SPI or i2c and that RTC device registers and probes after alarmtimer_init() registers and probes the 'alarmtimer' platform device. This is because system wide suspend suspends devices in the reverse order of their probe. When alarmtimer_suspend() attempts to program the RTC for a wakeup it will try to program an RTC device on a bus that has already been suspended. Move the alarmtimer device registration to happen when the RTC which is used for wakeup is registered. Register the 'alarmtimer' platform device as a child of the RTC device too, so that it can be guaranteed that the RTC device won't be suspended when alarmtimer_suspend() is called. Reported-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Stephen Boyd <swboyd@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20200124055849.154411-2-swboyd@chromium.org