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aa3449ee9c
linux/mm
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Linus Torvalds 50f5aa8a9b mm: don't pointlessly use BUG_ON() for sanity check 
BUG_ON() is a big hammer, and should be used _only_ if there is some
major corruption that you cannot possibly recover from, making it
imperative that the current process (and possibly the whole machine) be
terminated with extreme prejudice.

The trivial sanity check in the vmacache code is *not* such a fatal
error.  Recovering from it is absolutely trivial, and using BUG_ON()
just makes it harder to debug for no actual advantage.

To make matters worse, the placement of the BUG_ON() (only if the range
check matched) actually makes it harder to hit the sanity check to begin
with, so _if_ there is a bug (and we just got a report from Srivatsa
Bhat that this can indeed trigger), it is harder to debug not just
because the machine is possibly dead, but because we don't have better
coverage.

BUG_ON() must *die*.  Maybe we should add a checkpatch warning for it,
because it is simply just about the worst thing you can ever do if you
hit some "this cannot happen" situation.

Reported-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-28 14:24:09 -07:00
..
backing-dev.c bdi: avoid oops on device removal 2014-04-03 16:20:49 -07:00
balloon_compaction.c
bootmem.c
bounce.c
cleancache.c
compaction.c mm, compaction: determine isolation mode only once 2014-04-07 16:35:55 -07:00
debug-pagealloc.c
dmapool.c
early_ioremap.c mm: create generic early_ioremap() support 2014-04-07 16:36:15 -07:00
fadvise.c
failslab.c
filemap_xip.c
filemap.c mm: fix new kernel-doc warning in filemap.c 2014-04-18 16:40:09 -07:00
fremap.c
frontswap.c
highmem.c
huge_memory.c thp: close race between split and zap huge pages 2014-04-18 16:40:09 -07:00
hugetlb_cgroup.c
hugetlb.c mm/hugetlb.c: add cond_resched_lock() in return_unused_surplus_pages() 2014-04-18 16:40:08 -07:00
hwpoison-inject.c
init-mm.c
internal.h mm/readahead.c: inline ra_submit 2014-04-07 16:35:58 -07:00
interval_tree.c
iov_iter.c take iov_iter stuff to mm/iov_iter.c 2014-04-01 23:19:30 -04:00
Kconfig mm: create generic early_ioremap() support 2014-04-07 16:36:15 -07:00
Kconfig.debug
kmemcheck.c
kmemleak-test.c
kmemleak.c kmemleak: change some global variables to int 2014-04-03 16:20:50 -07:00
ksm.c
list_lru.c mm: keep page cache radix tree nodes in check 2014-04-03 16:21:01 -07:00
maccess.c
madvise.c
Makefile Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
memblock.c mm/memblock.c: use PFN_PHYS() 2014-04-07 16:35:58 -07:00
memcontrol.c memcg, slab: do not destroy children caches if parent has aliases 2014-04-07 16:36:13 -07:00
memory_hotplug.c
memory-failure.c Merge branch 'for-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2014-04-03 13:05:42 -07:00
memory.c mm: split 'tlb_flush_mmu()' into tlb flushing and memory freeing parts 2014-04-25 16:05:40 -07:00
mempolicy.c mm, mempolicy: remove per-process flag 2014-04-07 16:35:54 -07:00
mempool.c mempool: add unlikely and likely hints 2014-04-07 16:35:55 -07:00
migrate.c mm: fix swapops.h:131 bug if remap_file_pages raced migration 2014-03-20 22:09:09 -07:00
mincore.c mm + fs: prepare for non-page entries in page cache radix trees 2014-04-03 16:21:00 -07:00
mlock.c mm: try_to_unmap_cluster() should lock_page() before mlocking 2014-04-07 16:35:57 -07:00
mm_init.c
mmap.c mm: per-thread vma caching 2014-04-07 16:35:53 -07:00
mmu_context.c
mmu_notifier.c
mmzone.c
mprotect.c mm: move mmu notifier call from change_protection to change_pmd_range 2014-04-07 16:35:50 -07:00
mremap.c
msync.c
nobootmem.c mm/nobootmem.c: mark function as static 2014-04-03 16:21:02 -07:00
nommu.c mm: fix 'ERROR: do not initialise globals to 0 or NULL' and coding style 2014-04-07 16:35:55 -07:00
oom_kill.c
page_alloc.c mm/page_alloc.c: change mm debug routines back to EXPORT_SYMBOL 2014-04-07 16:35:59 -07:00
page_cgroup.c mm/page_cgroup.c: mark functions as static 2014-04-03 16:21:02 -07:00
page_io.c
page_isolation.c
page-writeback.c mm: remove unused arg of set_page_dirty_balance() 2014-04-07 16:35:57 -07:00
pagewalk.c
percpu-km.c
percpu-vm.c
percpu.c percpu: renew the max_contig if we merge the head and previous block 2014-03-29 09:29:42 -04:00
pgtable-generic.c
process_vm_access.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
quicklist.c
readahead.c mm/readahead.c: inline ra_submit 2014-04-07 16:35:58 -07:00
rmap.c mm: try_to_unmap_cluster() should lock_page() before mlocking 2014-04-07 16:35:57 -07:00
shmem.c mm: Initialize error in shmem_file_aio_read() 2014-04-13 14:10:26 -07:00
slab_common.c memcg, slab: do not destroy children caches if parent has aliases 2014-04-07 16:36:13 -07:00
slab.c Merge branch 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux 2014-04-13 13:28:13 -07:00
slab.h memcg, slab: never try to merge memcg caches 2014-04-07 16:36:12 -07:00
slob.c mm: slab/slub: use page->list consistently instead of page->lru 2014-04-11 10:06:06 +03:00
slub.c Merge branch 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux 2014-04-13 13:28:13 -07:00
sparse-vmemmap.c
sparse.c mm: use macros from compiler.h instead of __attribute__((...)) 2014-04-07 16:35:54 -07:00
swap_state.c
swap.c mm: thrash detection-based file cache sizing 2014-04-03 16:21:01 -07:00
swapfile.c
truncate.c mm: keep page cache radix tree nodes in check 2014-04-03 16:21:01 -07:00
util.c Merge git://git.infradead.org/users/eparis/audit 2014-04-12 12:38:53 -07:00
vmacache.c mm: don't pointlessly use BUG_ON() for sanity check 2014-04-28 14:24:09 -07:00
vmalloc.c mm/vmalloc.c: enhance vm_map_ram() comment 2014-04-07 16:35:55 -07:00
vmpressure.c
vmscan.c vmscan: reclaim_clean_pages_from_list() must use mod_zone_page_state() 2014-04-18 16:40:07 -07:00
vmstat.c CPU hotplug notifiers registration fixes for 3.15-rc1 2014-04-07 14:55:46 -07:00
workingset.c mm: keep page cache radix tree nodes in check 2014-04-03 16:21:01 -07:00
zbud.c
zsmalloc.c
zswap.c Merge branch 'akpm' (incoming from Andrew) 2014-04-07 16:38:06 -07:00