Ben Widawsky b7e3debdd0 mm/memory_hotplug.c: fix false softlockup during pfn range removal ... When working with very large nodes, poisoning the struct pages (for which there will be very many) can take a very long time. If the system is using voluntary preemptions, the software watchdog will not be able to detect forward progress. This patch addresses this issue by offering to give up time like __remove_pages() does. This behavior was introduced in v5.6 with: commit d33695b16a ("mm/memory_hotplug: poison memmap in remove_pfn_range_from_zone()") Alternately, init_page_poison could do this cond_resched(), but it seems to me that the caller of init_page_poison() is what actually knows whether or not it should relax its own priority. Based on Dan's notes, I think this is perfectly safe: commit f931ab479d ("mm: fix devm_memremap_pages crash, use mem_hotplug_{begin, done}") Aside from fixing the lockup, it is also a friendlier thing to do on lower core systems that might wipe out large chunks of hotplug memory (probably not a very common case). Fixes this kind of splat: watchdog: BUG: soft lockup - CPU#46 stuck for 22s! [daxctl:9922] irq event stamp: 138450 hardirqs last enabled at (138449): [<ffffffffa1001f26>] trace_hardirqs_on_thunk+0x1a/0x1c hardirqs last disabled at (138450): [<ffffffffa1001f42>] trace_hardirqs_off_thunk+0x1a/0x1c softirqs last enabled at (138448): [<ffffffffa1e00347>] __do_softirq+0x347/0x456 softirqs last disabled at (138443): [<ffffffffa10c416d>] irq_exit+0x7d/0xb0 CPU: 46 PID: 9922 Comm: daxctl Not tainted 5.7.0-BEN-14238-g373c6049b336 #30 Hardware name: Intel Corporation PURLEY/PURLEY, BIOS PLYXCRB1.86B.0578.D07.1902280810 02/28/2019 RIP: 0010:memset_erms+0x9/0x10 Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 <f3> aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 Call Trace: remove_pfn_range_from_zone+0x3a/0x380 memunmap_pages+0x17f/0x280 release_nodes+0x22a/0x260 __device_release_driver+0x172/0x220 device_driver_detach+0x3e/0xa0 unbind_store+0x113/0x130 kernfs_fop_write+0xdc/0x1c0 vfs_write+0xde/0x1d0 ksys_write+0x58/0xd0 do_syscall_64+0x5a/0x120 entry_SYSCALL_64_after_hwframe+0x49/0xb3 Built 2 zonelists, mobility grouping on. Total pages: 49050381 Policy zone: Normal Built 3 zonelists, mobility grouping on. Total pages: 49312525 Policy zone: Normal David said: "It really only is an issue for devmem. Ordinary hotplugged system memory is not affected (onlined/offlined in memory block granularity)." Link: http://lkml.kernel.org/r/20200619231213.1160351-1-ben.widawsky@intel.com Fixes: commit d33695b16a ("mm/memory_hotplug: poison memmap in remove_pfn_range_from_zone()") Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Reported-by: "Scargall, Steve" <steve.scargall@intel.com> Reported-by: Ben Widawsky <ben.widawsky@intel.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2020-06-26 00:27:38 -07:00
..
kasan
backing-dev.c
balloon_compaction.c
cleancache.c
cma_debug.c
cma.c
cma.h
compaction.c	mm, compaction: make capture control handling safe wrt interrupts	2020-06-26 00:27:36 -07:00
debug_page_ref.c
debug_vm_pgtable.c	mm/debug_vm_pgtable: fix build failure with powerpc 8xx	2020-06-26 00:27:37 -07:00
debug.c	maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault	2020-06-17 10:57:41 -07:00
dmapool.c
early_ioremap.c
fadvise.c
failslab.c
filemap.c
frame_vector.c
frontswap.c
gup_benchmark.c
gup.c	mm: Allow arches to provide ptep_get()	2020-06-20 22:14:53 +10:00
highmem.c
hmm.c
huge_memory.c
hugetlb_cgroup.c
hugetlb.c
hwpoison-inject.c
init-mm.c
internal.h
interval_tree.c
Kconfig
Kconfig.debug	treewide: replace '---help---' in Kconfig files with 'help'	2020-06-14 01:57:21 +09:00
khugepaged.c
kmemleak-test.c
kmemleak.c
ksm.c
list_lru.c
maccess.c	maccess: rename probe_user_{read,write} to copy_{from,to}_user_nofault	2020-06-17 10:57:41 -07:00
madvise.c
Makefile	The Kernel Concurrency Sanitizer (KCSAN)	2020-06-11 18:55:43 -07:00
mapping_dirty_helpers.c
memblock.c
memcontrol.c	mm/memcontrol.c: prevent missed memory.low load tears	2020-06-26 00:27:37 -07:00
memfd.c
memory_hotplug.c	mm/memory_hotplug.c: fix false softlockup during pfn range removal	2020-06-26 00:27:38 -07:00
memory-failure.c	mm/memory-failure: send SIGBUS(BUS_MCEERR_AR) only to current thread	2020-06-11 18:17:47 -07:00
memory.c	mm/memory: fix IO cost for anonymous page	2020-06-26 00:27:38 -07:00
mempolicy.c
mempool.c
memremap.c
memtest.c
migrate.c
mincore.c
mlock.c
mm_init.c
mmap.c
mmu_gather.c
mmu_notifier.c
mmzone.c
mprotect.c
mremap.c
msync.c
nommu.c	mm: remove vmalloc_exec	2020-06-26 00:27:38 -07:00
oom_kill.c	kernel: better document the use_mm/unuse_mm API contract	2020-06-10 19:14:18 -07:00
page_alloc.c
page_counter.c
page_ext.c
page_idle.c
page_io.c
page_isolation.c
page_owner.c
page_poison.c
page_reporting.c
page_reporting.h
page_vma_mapped.c
page-writeback.c
pagewalk.c
percpu-internal.h
percpu-km.c
percpu-stats.c
percpu-vm.c
percpu.c
pgtable-generic.c
process_vm_access.c
ptdump.c
readahead.c
rmap.c
rodata_test.c	maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault	2020-06-17 10:57:41 -07:00
shmem.c
shuffle.c
shuffle.h
slab_common.c	mm/slab: use memzero_explicit() in kzfree()	2020-06-26 00:27:37 -07:00
slab.c
slab.h	mm, slab: fix sign conversion problem in memcg_uncharge_slab()	2020-06-26 00:27:37 -07:00
slob.c
slub.c	slub: cure list_slab_objects() from double fix	2020-06-26 00:27:37 -07:00
sparse-vmemmap.c
sparse.c
swap_cgroup.c
swap_slots.c
swap_state.c	mm: fix swap cache node allocation mask	2020-06-26 00:27:37 -07:00
swap.c	mm/swap: fix for "mm: workingset: age nonresident information alongside anonymous pages"	2020-06-26 00:27:38 -07:00
swapfile.c
truncate.c
usercopy.c
userfaultfd.c
util.c
vmacache.c	kernel: better document the use_mm/unuse_mm API contract	2020-06-10 19:14:18 -07:00
vmalloc.c	mm: remove vmalloc_exec	2020-06-26 00:27:38 -07:00
vmpressure.c
vmscan.c	mm: workingset: age nonresident information alongside anonymous pages	2020-06-26 00:27:37 -07:00
vmstat.c
workingset.c	mm: workingset: age nonresident information alongside anonymous pages	2020-06-26 00:27:37 -07:00
z3fold.c
zbud.c
zpool.c
zsmalloc.c
zswap.c