Revision d8550860d910c6b7b70f830f59003b33daaa52c9 authored by Paul Burton on 03 March 2017, 23:26:05 UTC, committed by Ralf Baechle on 30 June 2017, 02:40:18 UTC
When the scheduler sets TIF_NEED_RESCHED & we call into the scheduler from arch/mips/kernel/entry.S we disable interrupts. This is true regardless of whether we reach work_resched from syscall_exit_work, resume_userspace or by looping after calling schedule(). Although we disable interrupts in these paths we don't call trace_hardirqs_off() before calling into C code which may acquire locks, and we therefore leave lockdep with an inconsistent view of whether interrupts are disabled or not when CONFIG_PROVE_LOCKING & CONFIG_DEBUG_LOCKDEP are both enabled. Without tracing this interrupt state lockdep will print warnings such as the following once a task returns from a syscall via syscall_exit_partial with TIF_NEED_RESCHED set: [ 49.927678] ------------[ cut here ]------------ [ 49.934445] WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:3687 check_flags.part.41+0x1dc/0x1e8 [ 49.946031] DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled) [ 49.946355] CPU: 0 PID: 1 Comm: init Not tainted 4.10.0-00439-gc9fd5d362289-dirty #197 [ 49.963505] Stack : 0000000000000000 ffffffff81bb5d6a 0000000000000006 ffffffff801ce9c4 [ 49.974431] 0000000000000000 0000000000000000 0000000000000000 000000000000004a [ 49.985300] ffffffff80b7e487 ffffffff80a24498 a8000000ff160000 ffffffff80ede8b8 [ 49.996194] 0000000000000001 0000000000000000 0000000000000000 0000000077c8030c [ 50.007063] 000000007fd8a510 ffffffff801cd45c 0000000000000000 a8000000ff127c88 [ 50.017945] 0000000000000000 ffffffff801cf928 0000000000000001 ffffffff80a24498 [ 50.028827] 0000000000000000 0000000000000001 0000000000000000 0000000000000000 [ 50.039688] 0000000000000000 a8000000ff127bd0 0000000000000000 ffffffff805509bc [ 50.050575] 00000000140084e0 0000000000000000 0000000000000000 0000000000040a00 [ 50.061448] 0000000000000000 ffffffff8010e1b0 0000000000000000 ffffffff805509bc [ 50.072327] ... [ 50.076087] Call Trace: [ 50.079869] [<ffffffff8010e1b0>] show_stack+0x80/0xa8 [ 50.086577] [<ffffffff805509bc>] dump_stack+0x10c/0x190 [ 50.093498] [<ffffffff8015dde0>] __warn+0xf0/0x108 [ 50.099889] [<ffffffff8015de34>] warn_slowpath_fmt+0x3c/0x48 [ 50.107241] [<ffffffff801c15b4>] check_flags.part.41+0x1dc/0x1e8 [ 50.114961] [<ffffffff801c239c>] lock_is_held_type+0x8c/0xb0 [ 50.122291] [<ffffffff809461b8>] __schedule+0x8c0/0x10f8 [ 50.129221] [<ffffffff80946a60>] schedule+0x30/0x98 [ 50.135659] [<ffffffff80106278>] work_resched+0x8/0x34 [ 50.142397] ---[ end trace 0cb4f6ef5b99fe21 ]--- [ 50.148405] possible reason: unannotated irqs-off. [ 50.154600] irq event stamp: 400463 [ 50.159566] hardirqs last enabled at (400463): [<ffffffff8094edc8>] _raw_spin_unlock_irqrestore+0x40/0xa8 [ 50.171981] hardirqs last disabled at (400462): [<ffffffff8094eb98>] _raw_spin_lock_irqsave+0x30/0xb0 [ 50.183897] softirqs last enabled at (400450): [<ffffffff8016580c>] __do_softirq+0x4ac/0x6a8 [ 50.195015] softirqs last disabled at (400425): [<ffffffff80165e78>] irq_exit+0x110/0x128 Fix this by using the TRACE_IRQS_OFF macro to call trace_hardirqs_off() when CONFIG_TRACE_IRQFLAGS is enabled. This is done before invoking schedule() following the work_resched label because: 1) Interrupts are disabled regardless of the path we take to reach work_resched() & schedule(). 2) Performing the tracing here avoids the need to do it in paths which disable interrupts but don't call out to C code before hitting a path which uses the RESTORE_SOME macro that will call trace_hardirqs_on() or trace_hardirqs_off() as appropriate. We call trace_hardirqs_on() using the TRACE_IRQS_ON macro before calling syscall_trace_leave() for similar reasons, ensuring that lockdep has a consistent view of state after we re-enable interrupts. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: linux-mips@linux-mips.org Cc: stable <stable@vger.kernel.org> Patchwork: https://patchwork.linux-mips.org/patch/15385/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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Kconfig | -rw-r--r-- | 23.9 KB |
Kconfig.debug | -rw-r--r-- | 3.8 KB |
Makefile | -rw-r--r-- | 3.5 KB |
backing-dev.c | -rw-r--r-- | 27.5 KB |
balloon_compaction.c | -rw-r--r-- | 4.7 KB |
bootmem.c | -rw-r--r-- | 20.8 KB |
cleancache.c | -rw-r--r-- | 9.9 KB |
cma.c | -rw-r--r-- | 13.5 KB |
cma.h | -rw-r--r-- | 534 bytes |
cma_debug.c | -rw-r--r-- | 4.5 KB |
compaction.c | -rw-r--r-- | 57.9 KB |
debug.c | -rw-r--r-- | 4.3 KB |
debug_page_ref.c | -rw-r--r-- | 1.3 KB |
dmapool.c | -rw-r--r-- | 13.7 KB |
early_ioremap.c | -rw-r--r-- | 6.2 KB |
fadvise.c | -rw-r--r-- | 4.3 KB |
failslab.c | -rw-r--r-- | 1.4 KB |
filemap.c | -rw-r--r-- | 79.8 KB |
frame_vector.c | -rw-r--r-- | 6.0 KB |
frontswap.c | -rw-r--r-- | 14.3 KB |
gup.c | -rw-r--r-- | 45.6 KB |
highmem.c | -rw-r--r-- | 11.7 KB |
huge_memory.c | -rw-r--r-- | 74.0 KB |
hugetlb.c | -rw-r--r-- | 127.8 KB |
hugetlb_cgroup.c | -rw-r--r-- | 10.9 KB |
hwpoison-inject.c | -rw-r--r-- | 3.2 KB |
init-mm.c | -rw-r--r-- | 680 bytes |
internal.h | -rw-r--r-- | 16.2 KB |
interval_tree.c | -rw-r--r-- | 3.1 KB |
khugepaged.c | -rw-r--r-- | 48.4 KB |
kmemcheck.c | -rw-r--r-- | 2.9 KB |
kmemleak-test.c | -rw-r--r-- | 3.2 KB |
kmemleak.c | -rw-r--r-- | 56.2 KB |
ksm.c | -rw-r--r-- | 65.5 KB |
list_lru.c | -rw-r--r-- | 12.6 KB |
maccess.c | -rw-r--r-- | 3.0 KB |
madvise.c | -rw-r--r-- | 21.5 KB |
memblock.c | -rw-r--r-- | 50.6 KB |
memcontrol.c | -rw-r--r-- | 154.6 KB |
memory-failure.c | -rw-r--r-- | 49.4 KB |
memory.c | -rw-r--r-- | 117.6 KB |
memory_hotplug.c | -rw-r--r-- | 55.5 KB |
mempolicy.c | -rw-r--r-- | 71.3 KB |
mempool.c | -rw-r--r-- | 13.9 KB |
memtest.c | -rw-r--r-- | 2.7 KB |
migrate.c | -rw-r--r-- | 52.2 KB |
mincore.c | -rw-r--r-- | 6.7 KB |
mlock.c | -rw-r--r-- | 22.6 KB |
mm_init.c | -rw-r--r-- | 4.8 KB |
mmap.c | -rw-r--r-- | 96.2 KB |
mmu_context.c | -rw-r--r-- | 1.3 KB |
mmu_notifier.c | -rw-r--r-- | 11.5 KB |
mmzone.c | -rw-r--r-- | 2.4 KB |
mprotect.c | -rw-r--r-- | 13.5 KB |
mremap.c | -rw-r--r-- | 16.2 KB |
msync.c | -rw-r--r-- | 2.6 KB |
nobootmem.c | -rw-r--r-- | 11.1 KB |
nommu.c | -rw-r--r-- | 48.6 KB |
oom_kill.c | -rw-r--r-- | 28.5 KB |
page-writeback.c | -rw-r--r-- | 84.5 KB |
page_alloc.c | -rw-r--r-- | 209.4 KB |
page_counter.c | -rw-r--r-- | 4.8 KB |
page_ext.c | -rw-r--r-- | 11.1 KB |
page_idle.c | -rw-r--r-- | 5.4 KB |
page_io.c | -rw-r--r-- | 9.4 KB |
page_isolation.c | -rw-r--r-- | 8.3 KB |
page_owner.c | -rw-r--r-- | 14.7 KB |
page_poison.c | -rw-r--r-- | 2.6 KB |
page_vma_mapped.c | -rw-r--r-- | 5.8 KB |
pagewalk.c | -rw-r--r-- | 8.4 KB |
percpu-km.c | -rw-r--r-- | 2.8 KB |
percpu-vm.c | -rw-r--r-- | 10.0 KB |
percpu.c | -rw-r--r-- | 66.8 KB |
pgtable-generic.c | -rw-r--r-- | 5.2 KB |
process_vm_access.c | -rw-r--r-- | 10.1 KB |
quicklist.c | -rw-r--r-- | 2.4 KB |
readahead.c | -rw-r--r-- | 16.1 KB |
rmap.c | -rw-r--r-- | 48.0 KB |
rodata_test.c | -rw-r--r-- | 1.4 KB |
shmem.c | -rw-r--r-- | 110.3 KB |
slab.c | -rw-r--r-- | 110.4 KB |
slab.h | -rw-r--r-- | 14.7 KB |
slab_common.c | -rw-r--r-- | 34.4 KB |
slob.c | -rw-r--r-- | 16.0 KB |
slub.c | -rw-r--r-- | 140.5 KB |
sparse-vmemmap.c | -rw-r--r-- | 8.1 KB |
sparse.c | -rw-r--r-- | 20.7 KB |
swap.c | -rw-r--r-- | 27.0 KB |
swap_cgroup.c | -rw-r--r-- | 4.7 KB |
swap_slots.c | -rw-r--r-- | 8.9 KB |
swap_state.c | -rw-r--r-- | 14.3 KB |
swapfile.c | -rw-r--r-- | 84.6 KB |
truncate.c | -rw-r--r-- | 25.3 KB |
usercopy.c | -rw-r--r-- | 7.5 KB |
userfaultfd.c | -rw-r--r-- | 14.3 KB |
util.c | -rw-r--r-- | 18.1 KB |
vmacache.c | -rw-r--r-- | 3.2 KB |
vmalloc.c | -rw-r--r-- | 70.2 KB |
vmpressure.c | -rw-r--r-- | 12.8 KB |
vmscan.c | -rw-r--r-- | 113.4 KB |
vmstat.c | -rw-r--r-- | 47.4 KB |
workingset.c | -rw-r--r-- | 18.4 KB |
z3fold.c | -rw-r--r-- | 23.8 KB |
zbud.c | -rw-r--r-- | 18.2 KB |
zpool.c | -rw-r--r-- | 10.0 KB |
zsmalloc.c | -rw-r--r-- | 59.3 KB |
zswap.c | -rw-r--r-- | 32.8 KB |
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