user/sven/linux.git/kernel/jump_label.c, branch v4.9.280

jump_label: Invoke jump_label_test() via early_initcall()

2017-12-14T08:28:24Z

[ Upstream commit 92ee46efeb505ead3ab06d3c5ce695637ed5f152 ] Fengguang Wu reported that running the rcuperf test during boot can cause the jump_label_test() to hit a WARN_ON(). The issue is that the core jump label code relies on kernel_text_address() to detect when it can no longer update branches that may be contained in __init sections. The kernel_text_address() in turn assumes that if the system_state variable is greter than or equal to SYSTEM_RUNNING then __init sections are no longer valid (since the assumption is that they have been freed). However, when rcuperf is setup to run in early boot it can call kernel_power_off() which sets the system_state to SYSTEM_POWER_OFF. Since rcuperf initialization is invoked via a module_init(), we can make the dependency of jump_label_test() needing to complete before rcuperf explicit by calling it via early_initcall(). Reported-by: Fengguang Wu Signed-off-by: Jason Baron Acked-by: Paul E. McKenney Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1510609727-2238-1-git-send-email-jbaron@akamai.com Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

jump_labels: API for flushing deferred jump label updates

2017-01-19T19:17:59Z

commit b6416e61012429e0277bd15a229222fd17afc1c1 upstream. Modules that use static_key_deferred need a way to synchronize with any delayed work that is still pending when the module is unloaded. Introduce static_key_deferred_flush() which flushes any pending jump label updates. Signed-off-by: David Matlack Acked-by: Peter Zijlstra (Intel) Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

Merge tag 'powerpc-4.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2016-08-05T13:00:54Z

Pull more powerpc updates from Michael Ellerman: "These were delayed for various reasons, so I let them sit in next a bit longer, rather than including them in my first pull request. Fixes: - Fix early access to cpu_spec relocation from Benjamin Herrenschmidt - Fix incorrect event codes in power9-event-list from Madhavan Srinivasan - Move register_process_table() out of ppc_md from Michael Ellerman Use jump_label use for [cpu|mmu]_has_feature(): - Add mmu_early_init_devtree() from Michael Ellerman - Move disable_radix handling into mmu_early_init_devtree() from Michael Ellerman - Do hash device tree scanning earlier from Michael Ellerman - Do radix device tree scanning earlier from Michael Ellerman - Do feature patching before MMU init from Michael Ellerman - Check features don't change after patching from Michael Ellerman - Make MMU_FTR_RADIX a MMU family feature from Aneesh Kumar K.V - Convert mmu_has_feature() to returning bool from Michael Ellerman - Convert cpu_has_feature() to returning bool from Michael Ellerman - Define radix_enabled() in one place & use static inline from Michael Ellerman - Add early_[cpu|mmu]_has_feature() from Michael Ellerman - Convert early cpu/mmu feature check to use the new helpers from Aneesh Kumar K.V - jump_label: Make it possible for arches to invoke jump_label_init() earlier from Kevin Hao - Call jump_label_init() in apply_feature_fixups() from Aneesh Kumar K.V - Remove mfvtb() from Kevin Hao - Move cpu_has_feature() to a separate file from Kevin Hao - Add kconfig option to use jump labels for cpu/mmu_has_feature() from Michael Ellerman - Add option to use jump label for cpu_has_feature() from Kevin Hao - Add option to use jump label for mmu_has_feature() from Kevin Hao - Catch usage of cpu/mmu_has_feature() before jump label init from Aneesh Kumar K.V - Annotate jump label assembly from Michael Ellerman TLB flush enhancements from Aneesh Kumar K.V: - radix: Implement tlb mmu gather flush efficiently - Add helper for finding SLBE LLP encoding - Use hugetlb flush functions - Drop multiple definition of mm_is_core_local - radix: Add tlb flush of THP ptes - radix: Rename function and drop unused arg - radix/hugetlb: Add helper for finding page size - hugetlb: Add flush_hugetlb_tlb_range - remove flush_tlb_page_nohash Add new ptrace regsets from Anshuman Khandual and Simon Guo: - elf: Add powerpc specific core note sections - Add the function flush_tmregs_to_thread - Enable in transaction NT_PRFPREG ptrace requests - Enable in transaction NT_PPC_VMX ptrace requests - Enable in transaction NT_PPC_VSX ptrace requests - Adapt gpr32_get, gpr32_set functions for transaction - Enable support for NT_PPC_CGPR - Enable support for NT_PPC_CFPR - Enable support for NT_PPC_CVMX - Enable support for NT_PPC_CVSX - Enable support for TM SPR state - Enable NT_PPC_TM_CTAR, NT_PPC_TM_CPPR, NT_PPC_TM_CDSCR - Enable support for NT_PPPC_TAR, NT_PPC_PPR, NT_PPC_DSCR - Enable support for EBB registers - Enable support for Performance Monitor registers" * tag 'powerpc-4.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (48 commits) powerpc/mm: Move register_process_table() out of ppc_md powerpc/perf: Fix incorrect event codes in power9-event-list powerpc/32: Fix early access to cpu_spec relocation powerpc/ptrace: Enable support for Performance Monitor registers powerpc/ptrace: Enable support for EBB registers powerpc/ptrace: Enable support for NT_PPPC_TAR, NT_PPC_PPR, NT_PPC_DSCR powerpc/ptrace: Enable NT_PPC_TM_CTAR, NT_PPC_TM_CPPR, NT_PPC_TM_CDSCR powerpc/ptrace: Enable support for TM SPR state powerpc/ptrace: Enable support for NT_PPC_CVSX powerpc/ptrace: Enable support for NT_PPC_CVMX powerpc/ptrace: Enable support for NT_PPC_CFPR powerpc/ptrace: Enable support for NT_PPC_CGPR powerpc/ptrace: Adapt gpr32_get, gpr32_set functions for transaction powerpc/ptrace: Enable in transaction NT_PPC_VSX ptrace requests powerpc/ptrace: Enable in transaction NT_PPC_VMX ptrace requests powerpc/ptrace: Enable in transaction NT_PRFPREG ptrace requests powerpc/process: Add the function flush_tmregs_to_thread elf: Add powerpc specific core note sections powerpc/mm: remove flush_tlb_page_nohash powerpc/mm/hugetlb: Add flush_hugetlb_tlb_range ...

Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

2016-08-04T13:14:38Z

Pull module updates from Rusty Russell: "The only interesting thing here is Jessica's patch to add ro_after_init support to modules. The rest are all trivia" * tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: extable.h: add stddef.h so "NULL" definition is not implicit modules: add ro_after_init support jump_label: disable preemption around __module_text_address(). exceptions: fork exception table content from module.h into extable.h modules: Add kernel parameter to blacklist modules module: Do a WARN_ON_ONCE() for assert module mutex not held Documentation/module-signing.txt: Note need for version info if reusing a key module: Invalidate signatures on force-loaded modules module: Issue warnings when tainting kernel module: fix redundant test. module: fix noreturn attribute for __module_put_and_exit()

jump_label: remove bug.h, atomic.h dependencies for HAVE_JUMP_LABEL

2016-08-04T12:50:07Z

The current jump_label.h includes bug.h for things such as WARN_ON(). This makes the header problematic for inclusion by kernel.h or any headers that kernel.h includes, since bug.h includes kernel.h (circular dependency). The inclusion of atomic.h is similarly problematic. Thus, this should make jump_label.h 'includable' from most places. Link: http://lkml.kernel.org/r/7060ce35ddd0d20b33bf170685e6b0fab816bdf2.1467837322.git.jbaron@akamai.com Signed-off-by: Jason Baron Cc: "David S. Miller" Cc: Arnd Bergmann Cc: Benjamin Herrenschmidt Cc: Chris Metcalf Cc: Heiko Carstens Cc: Joe Perches Cc: Martin Schwidefsky Cc: Michael Ellerman Cc: Paul Mackerras Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

jump_label: disable preemption around __module_text_address().

2016-08-04T00:46:54Z

Steven reported a warning caused by not holding module_mutex or rcu_read_lock_sched: his backtrace was corrupted but a quick audit found this possible cause. It's wrong anyway... Reported-by: Steven Rostedt Signed-off-by: Rusty Russell

jump_label: Make it possible for arches to invoke jump_label_init() earlier

2016-08-01T01:15:01Z

Some arches (powerpc at least) would like to invoke jump_label_init() much earlier in boot. So check static_key_initialized in order to make sure this function runs only once. LGTM-by: Ingo (http://marc.info/?l=linux-kernel&m=144049104329961&w=2) Signed-off-by: Kevin Hao Signed-off-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman

Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2016-07-25T19:41:29Z

Pull locking updates from Ingo Molnar: "The locking tree was busier in this cycle than the usual pattern - a couple of major projects happened to coincide. The main changes are: - implement the atomic_fetch_{add,sub,and,or,xor}() API natively across all SMP architectures (Peter Zijlstra) - add atomic_fetch_{inc/dec}() as well, using the generic primitives (Davidlohr Bueso) - optimize various aspects of rwsems (Jason Low, Davidlohr Bueso, Waiman Long) - optimize smp_cond_load_acquire() on arm64 and implement LSE based atomic{,64}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}() on arm64 (Will Deacon) - introduce smp_acquire__after_ctrl_dep() and fix various barrier mis-uses and bugs (Peter Zijlstra) - after discovering ancient spin_unlock_wait() barrier bugs in its implementation and usage, strengthen its semantics and update/fix usage sites (Peter Zijlstra) - optimize mutex_trylock() fastpath (Peter Zijlstra) - ... misc fixes and cleanups" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (67 commits) locking/atomic: Introduce inc/dec variants for the atomic_fetch_$op() API locking/barriers, arch/arm64: Implement LDXR+WFE based smp_cond_load_acquire() locking/static_keys: Fix non static symbol Sparse warning locking/qspinlock: Use __this_cpu_dec() instead of full-blown this_cpu_dec() locking/atomic, arch/tile: Fix tilepro build locking/atomic, arch/m68k: Remove comment locking/atomic, arch/arc: Fix build locking/Documentation: Clarify limited control-dependency scope locking/atomic, arch/rwsem: Employ atomic_long_fetch_add() locking/atomic, arch/qrwlock: Employ atomic_fetch_add_acquire() locking/atomic, arch/mips: Convert to _relaxed atomics locking/atomic, arch/alpha: Convert to _relaxed atomics locking/atomic: Remove the deprecated atomic_{set,clear}_mask() functions locking/atomic: Remove linux/atomic.h:atomic_fetch_or() locking/atomic: Implement atomic{,64,_long}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}() locking/atomic: Fix atomic64_relaxed() bits locking/atomic, arch/xtensa: Implement atomic_fetch_{add,sub,and,or,xor}() locking/atomic, arch/x86: Implement atomic{,64}_fetch_{add,sub,and,or,xor}() locking/atomic, arch/tile: Implement atomic{,64}_fetch_{add,sub,and,or,xor}() locking/atomic, arch/sparc: Implement atomic{,64}_fetch_{add,sub,and,or,xor}() ...

locking/static_keys: Fix non static symbol Sparse warning

2016-07-07T07:06:46Z

Fix the following sparse warnings: kernel/jump_label.c:473:23: warning: symbol 'jump_label_module_nb' was not declared. Should it be static? Signed-off-by: Wei Yongjun Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1466183980-8903-1-git-send-email-weiyj_lk@163.com Signed-off-by: Ingo Molnar

locking/static_key: Fix concurrent static_key_slow_inc()

2016-06-24T06:23:16Z

The following scenario is possible: CPU 1 CPU 2 static_key_slow_inc() atomic_inc_not_zero() -> key.enabled == 0, no increment jump_label_lock() atomic_inc_return() -> key.enabled == 1 now static_key_slow_inc() atomic_inc_not_zero() -> key.enabled == 1, inc to 2 return ** static key is wrong! jump_label_update() jump_label_unlock() Testing the static key at the point marked by (**) will follow the wrong path for jumps that have not been patched yet. This can actually happen when creating many KVM virtual machines with userspace LAPIC emulation; just run several copies of the following program: #include #include #include #include int main(void) { for (;;) { int kvmfd = open("/dev/kvm", O_RDONLY); int vmfd = ioctl(kvmfd, KVM_CREATE_VM, 0); close(ioctl(vmfd, KVM_CREATE_VCPU, 1)); close(vmfd); close(kvmfd); } return 0; } Every KVM_CREATE_VCPU ioctl will attempt a static_key_slow_inc() call. The static key's purpose is to skip NULL pointer checks and indeed one of the processes eventually dereferences NULL. As explained in the commit that introduced the bug: 706249c222f6 ("locking/static_keys: Rework update logic") jump_label_update() needs key.enabled to be true. The solution adopted here is to temporarily make key.enabled == -1, and use go down the slow path when key.enabled <= 0. Reported-by: Dmitry Vyukov Signed-off-by: Paolo Bonzini Signed-off-by: Peter Zijlstra (Intel) Cc: # v4.3+ Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: 706249c222f6 ("locking/static_keys: Rework update logic") Link: http://lkml.kernel.org/r/1466527937-69798-1-git-send-email-pbonzini@redhat.com [ Small stylistic edits to the changelog and the code. ] Signed-off-by: Ingo Molnar