linux/kernel/bpf/stackmap.c, branch v5.8

mmap locking API: add mmap_read_trylock_non_owner()

2020-06-09T16:39:14Z

Add a couple APIs used by kernel/bpf/stackmap.c only: - mmap_read_trylock_non_owner() - mmap_read_unlock_non_owner() (may be called from a work queue). It's still not ideal that bpf/stackmap subverts the lock ownership in this way. Thanks to Peter Zijlstra for suggesting this API as the least-ugly way of addressing this in the short term. Signed-off-by: Michel Lespinasse Signed-off-by: Andrew Morton Reviewed-by: Daniel Jordan Reviewed-by: Vlastimil Babka Reviewed-by: Davidlohr Bueso Cc: David Rientjes Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: Jerome Glisse Cc: John Hubbard Cc: Laurent Dufour Cc: Liam Howlett Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Ying Han Link: http://lkml.kernel.org/r/20200520052908.204642-8-walken@google.com Signed-off-by: Linus Torvalds

mmap locking API: use coccinelle to convert mmap_sem rwsem call sites

2020-06-09T16:39:14Z

This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse Signed-off-by: Andrew Morton Reviewed-by: Daniel Jordan Reviewed-by: Laurent Dufour Reviewed-by: Vlastimil Babka Cc: Davidlohr Bueso Cc: David Rientjes Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: Jerome Glisse Cc: John Hubbard Cc: Liam Howlett Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Ying Han Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds

bpf: Implement CAP_BPF

2020-05-15T15:29:41Z

Implement permissions as stated in uapi/linux/capability.h In order to do that the verifier allow_ptr_leaks flag is split into four flags and they are set as: env->allow_ptr_leaks = bpf_allow_ptr_leaks(); env->bypass_spec_v1 = bpf_bypass_spec_v1(); env->bypass_spec_v4 = bpf_bypass_spec_v4(); env->bpf_capable = bpf_capable(); The first three currently equivalent to perfmon_capable(), since leaking kernel pointers and reading kernel memory via side channel attacks is roughly equivalent to reading kernel memory with cap_perfmon. 'bpf_capable' enables bounded loops, precision tracking, bpf to bpf calls and other verifier features. 'allow_ptr_leaks' enable ptr leaks, ptr conversions, subtraction of pointers. 'bypass_spec_v1' disables speculative analysis in the verifier, run time mitigations in bpf array, and enables indirect variable access in bpf programs. 'bypass_spec_v4' disables emission of sanitation code by the verifier. That means that the networking BPF program loaded with CAP_BPF + CAP_NET_ADMIN will have speculative checks done by the verifier and other spectre mitigation applied. Such networking BPF program will not be able to leak kernel pointers and will not be able to access arbitrary kernel memory. Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20200513230355.7858-3-alexei.starovoitov@gmail.com

bpf/stackmap: Dont trylock mmap_sem with PREEMPT_RT and interrupts disabled

2020-02-25T00:20:10Z

In a RT kernel down_read_trylock() cannot be used from NMI context and up_read_non_owner() is another problematic issue. So in such a configuration, simply elide the annotated stackmap and just report the raw IPs. In the longer term, it might be possible to provide a atomic friendly versions of the page cache traversal which will at least provide the info if the pages are resident and don't need to be paged in. [ tglx: Use IS_ENABLED() to avoid the #ifdeffery, fixup the irq work callback and add a comment ] Signed-off-by: David S. Miller Signed-off-by: Thomas Gleixner Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200224145644.708960317@linutronix.de

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

2019-12-03T17:29:50Z

Pull irq updates from Ingo Molnar: "Most of the IRQ subsystem changes in this cycle were irq-chip driver updates: - Qualcomm PDC wakeup interrupt support - Layerscape external IRQ support - Broadcom bcm7038 PM and wakeup support - Ingenic driver cleanup and modernization - GICv3 ITS preparation for GICv4.1 updates - GICv4 fixes There's also the series from Frederic Weisbecker that fixes memory ordering bugs for the irq-work logic, whose primary fix is to turn work->irq_work.flags into an atomic variable and then convert the complex (and buggy) atomic_cmpxchg() loop in irq_work_claim() into a much simpler atomic_fetch_or() call. There are also various smaller cleanups" * 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (44 commits) pinctrl/sdm845: Add PDC wakeup interrupt map for GPIOs pinctrl/msm: Setup GPIO chip in hierarchy irqchip/qcom-pdc: Add irqchip set/get state calls irqchip/qcom-pdc: Add irqdomain for wakeup capable GPIOs irqchip/qcom-pdc: Do not toggle IRQ_ENABLE during mask/unmask irqchip/qcom-pdc: Update max PDC interrupts of/irq: Document properties for wakeup interrupt parent genirq: Introduce irq_chip_get/set_parent_state calls irqdomain: Add bus token DOMAIN_BUS_WAKEUP genirq: Fix function documentation of __irq_alloc_descs() irq_work: Fix IRQ_WORK_BUSY bit clearing irqchip/ti-sci-inta: Use ERR_CAST inlined function instead of ERR_PTR(PTR_ERR(...)) irq_work: Slightly simplify IRQ_WORK_PENDING clearing irq_work: Fix irq_work_claim() memory ordering irq_work: Convert flags to atomic_t irqchip: Ingenic: Add process for more than one irq at the same time. irqchip: ingenic: Alloc generic chips from IRQ domain irqchip: ingenic: Get virq number from IRQ domain irqchip: ingenic: Error out if IRQ domain creation failed irqchip: ingenic: Drop redundant irq_suspend / irq_resume functions ...

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

2019-11-27T00:02:40Z

Pull locking updates from Ingo Molnar: "The main changes in this cycle were: - A comprehensive rewrite of the robust/PI futex code's exit handling to fix various exit races. (Thomas Gleixner et al) - Rework the generic REFCOUNT_FULL implementation using atomic_fetch_* operations so that the performance impact of the cmpxchg() loops is mitigated for common refcount operations. With these performance improvements the generic implementation of refcount_t should be good enough for everybody - and this got confirmed by performance testing, so remove ARCH_HAS_REFCOUNT and REFCOUNT_FULL entirely, leaving the generic implementation enabled unconditionally. (Will Deacon) - Other misc changes, fixes, cleanups" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits) lkdtm: Remove references to CONFIG_REFCOUNT_FULL locking/refcount: Remove unused 'refcount_error_report()' function locking/refcount: Consolidate implementations of refcount_t locking/refcount: Consolidate REFCOUNT_{MAX,SATURATED} definitions locking/refcount: Move saturation warnings out of line locking/refcount: Improve performance of generic REFCOUNT_FULL code locking/refcount: Move the bulk of the REFCOUNT_FULL implementation into the header locking/refcount: Remove unused refcount_*_checked() variants locking/refcount: Ensure integer operands are treated as signed locking/refcount: Define constants for saturation and max refcount values futex: Prevent exit livelock futex: Provide distinct return value when owner is exiting futex: Add mutex around futex exit futex: Provide state handling for exec() as well futex: Sanitize exit state handling futex: Mark the begin of futex exit explicitly futex: Set task::futex_state to DEAD right after handling futex exit futex: Split futex_mm_release() for exit/exec exit/exec: Seperate mm_release() futex: Replace PF_EXITPIDONE with a state ...

irq_work: Convert flags to atomic_t

2019-11-11T08:02:56Z

We need to convert flags to atomic_t in order to later fix an ordering issue on atomic_cmpxchg() failure. This will allow us to use atomic_fetch_or(). Also clarify the nature of those flags. [ mingo: Converted two more usage site the original patch missed. ] Signed-off-by: Frederic Weisbecker Cc: Linus Torvalds Cc: Paul E . McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Link: https://lkml.kernel.org/r/20191108160858.31665-2-frederic@kernel.org Signed-off-by: Ingo Molnar

bpf/stackmap: Fix deadlock with rq_lock in bpf_get_stack()

2019-10-16T17:37:52Z

bpf stackmap with build-id lookup (BPF_F_STACK_BUILD_ID) can trigger A-A deadlock on rq_lock(): rcu: INFO: rcu_sched detected stalls on CPUs/tasks: [...] Call Trace: try_to_wake_up+0x1ad/0x590 wake_up_q+0x54/0x80 rwsem_wake+0x8a/0xb0 bpf_get_stack+0x13c/0x150 bpf_prog_fbdaf42eded9fe46_on_event+0x5e3/0x1000 bpf_overflow_handler+0x60/0x100 __perf_event_overflow+0x4f/0xf0 perf_swevent_overflow+0x99/0xc0 ___perf_sw_event+0xe7/0x120 __schedule+0x47d/0x620 schedule+0x29/0x90 futex_wait_queue_me+0xb9/0x110 futex_wait+0x139/0x230 do_futex+0x2ac/0xa50 __x64_sys_futex+0x13c/0x180 do_syscall_64+0x42/0x100 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This can be reproduced by: 1. Start a multi-thread program that does parallel mmap() and malloc(); 2. taskset the program to 2 CPUs; 3. Attach bpf program to trace_sched_switch and gather stackmap with build-id, e.g. with trace.py from bcc tools: trace.py -U -p -s t:sched:sched_switch A sample reproducer is attached at the end. This could also trigger deadlock with other locks that are nested with rq_lock. Fix this by checking whether irqs are disabled. Since rq_lock and all other nested locks are irq safe, it is safe to do up_read() when irqs are not disable. If the irqs are disabled, postpone up_read() in irq_work. Fixes: 615755a77b24 ("bpf: extend stackmap to save binary_build_id+offset instead of address") Signed-off-by: Song Liu Signed-off-by: Alexei Starovoitov Cc: Peter Zijlstra Cc: Alexei Starovoitov Cc: Daniel Borkmann Link: https://lore.kernel.org/bpf/20191014171223.357174-1-songliubraving@fb.com Reproducer: ============================ 8< ============================ char *filename; void *worker(void *p) { void *ptr; int fd; char *pptr; fd = open(filename, O_RDONLY); if (fd < 0) return NULL; while (1) { struct timespec ts = {0, 1000 + rand() % 2000}; ptr = mmap(NULL, 4096 * 64, PROT_READ, MAP_PRIVATE, fd, 0); usleep(1); if (ptr == MAP_FAILED) { printf("failed to mmap\n"); break; } munmap(ptr, 4096 * 64); usleep(1); pptr = malloc(1); usleep(1); pptr[0] = 1; usleep(1); free(pptr); usleep(1); nanosleep(&ts, NULL); } close(fd); return NULL; } int main(int argc, char *argv[]) { void *ptr; int i; pthread_t threads[THREAD_COUNT]; if (argc < 2) return 0; filename = argv[1]; for (i = 0; i < THREAD_COUNT; i++) { if (pthread_create(threads + i, NULL, worker, NULL)) { fprintf(stderr, "Error creating thread\n"); return 0; } } for (i = 0; i < THREAD_COUNT; i++) pthread_join(threads[i], NULL); return 0; } ============================ 8< ============================

locking/lockdep: Remove unused @nested argument from lock_release()

2019-10-09T10:46:10Z

Since the following commit: b4adfe8e05f1 ("locking/lockdep: Remove unused argument in __lock_release") @nested is no longer used in lock_release(), so remove it from all lock_release() calls and friends. Signed-off-by: Qian Cai Signed-off-by: Peter Zijlstra (Intel) Acked-by: Will Deacon Acked-by: Daniel Vetter Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: airlied@linux.ie Cc: akpm@linux-foundation.org Cc: alexander.levin@microsoft.com Cc: daniel@iogearbox.net Cc: davem@davemloft.net Cc: dri-devel@lists.freedesktop.org Cc: duyuyang@gmail.com Cc: gregkh@linuxfoundation.org Cc: hannes@cmpxchg.org Cc: intel-gfx@lists.freedesktop.org Cc: jack@suse.com Cc: jlbec@evilplan.or Cc: joonas.lahtinen@linux.intel.com Cc: joseph.qi@linux.alibaba.com Cc: jslaby@suse.com Cc: juri.lelli@redhat.com Cc: maarten.lankhorst@linux.intel.com Cc: mark@fasheh.com Cc: mhocko@kernel.org Cc: mripard@kernel.org Cc: ocfs2-devel@oss.oracle.com Cc: rodrigo.vivi@intel.com Cc: sean@poorly.run Cc: st@kernel.org Cc: tj@kernel.org Cc: tytso@mit.edu Cc: vdavydov.dev@gmail.com Cc: vincent.guittot@linaro.org Cc: viro@zeniv.linux.org.uk Link: https://lkml.kernel.org/r/1568909380-32199-1-git-send-email-cai@lca.pw Signed-off-by: Ingo Molnar

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2019-06-07T18:00:14Z

Some ISDN files that got removed in net-next had some changes done in mainline, take the removals. Signed-off-by: David S. Miller