linux/mm
Hugh Dickins 3dc147414c badpage: replace page_remove_rmap Eeek and BUG
Now that bad pages are kept out of circulation, there is no need for the
infamous page_remove_rmap() BUG() - once that page is freed, its negative
mapcount will issue a "Bad page state" message and the page won't be
freed.  Removing the BUG() allows more info, on subsequent pages, to be
gathered.

We do have more info about the page at this point than bad_page() can know
- notably, what the pmd is, which might pinpoint something like low 64kB
corruption - but page_remove_rmap() isn't given the address to find that.

In practice, there is only one call to page_remove_rmap() which has ever
reported anything, that from zap_pte_range() (usually on exit, sometimes
on munmap).  It has all the info, so remove page_remove_rmap()'s "Eeek"
message and leave it all to zap_pte_range().

mm/memory.c already has a hardly used print_bad_pte() function, showing
some of the appropriate info: extend it to show what we want for the rmap
case: pte info, page info (when there is a page) and vma info to compare.
zap_pte_range() already knows the pmd, but print_bad_pte() is easier to
use if it works that out for itself.

Some of this info is also shown in bad_page()'s "Bad page state" message.
Keep them separate, but adjust them to match each other as far as
possible.  Say "Bad page map" in print_bad_pte(), and add a TAINT_BAD_PAGE
there too.

print_bad_pte() show current->comm unconditionally (though it should get
repeated in the usually irrelevant stack trace): sorry, I misled Nick
Piggin to make it conditional on vm_mm == current->mm, but current->mm is
already NULL in the exit case.  Usually current->comm is good, though
exceptionally it may not be that of the mm (when "swapoff" for example).

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-06 15:59:07 -08:00
..
allocpercpu.c mm/allocpercpu.c: make 4 functions static 2008-07-26 12:00:12 -07:00
backing-dev.c mm: change dirty limit type specifiers to unsigned long 2009-01-06 15:59:02 -08:00
bootmem.c misc: replace __FUNCTION__ with __func__ 2008-10-16 11:21:30 -07:00
bounce.c bounce: don't rely on a zeroed bio_vec list 2008-12-29 08:29:52 +01:00
dmapool.c dmapool: enable debugging for CONFIG_SLUB_DEBUG_ON too 2008-04-28 08:58:20 -07:00
fadvise.c Remove Andrew Morton's old email accounts 2008-10-16 11:21:32 -07:00
failslab.c SLUB: failslab support 2008-12-29 11:27:46 +02:00
filemap_xip.c mm: xip/ext2 fix block allocation race 2008-08-20 15:40:32 -07:00
filemap.c mm: write_cache_pages integrity fix 2009-01-06 15:58:59 -08:00
fremap.c mmap: handle mlocked pages during map, remap, unmap 2008-10-20 08:52:31 -07:00
highmem.c x86, pat: avoid highmem cache attribute aliasing 2008-08-15 17:22:57 +02:00
hugetlb.c hugetlb: fix sparse warnings 2009-01-06 15:59:06 -08:00
internal.h hugetlb: pull gigantic page initialisation out of the default path 2008-11-06 15:41:18 -08:00
Kconfig Unevictable LRU Infrastructure 2008-10-20 08:50:26 -07:00
maccess.c kgdb: fix optional arch functions and probe_kernel_* 2008-04-17 20:05:39 +02:00
madvise.c madvise: update function comment of madvise_dontneed 2008-07-30 09:41:45 -07:00
Makefile SLUB: failslab support 2008-12-29 11:27:46 +02:00
memcontrol.c mm: make mem_cgroup_resize_limit() static 2009-01-06 15:59:04 -08:00
memory_hotplug.c mm: remove GFP_HIGHUSER_PAGECACHE 2009-01-06 15:59:01 -08:00
memory.c badpage: replace page_remove_rmap Eeek and BUG 2009-01-06 15:59:07 -08:00
mempolicy.c Merge branch 'master' into next 2008-11-14 11:29:12 +11:00
mempool.c spelling fixes: mm/ 2007-10-20 01:27:18 +02:00
migrate.c mm: add Set,ClearPageSwapCache stubs 2009-01-06 15:59:02 -08:00
mincore.c mm: remove nopage 2008-04-28 08:58:18 -07:00
mlock.c x86, bts: memory accounting 2008-12-20 09:15:47 +01:00
mm_init.c mm: mminit_loglevel cannot be __meminitdata anymore 2008-08-20 15:40:30 -07:00
mmap.c mm: update my address 2009-01-05 17:44:42 -08:00
mmu_notifier.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
mmzone.c mm: mark the correct zone as full when scanning zonelists 2008-09-13 14:41:52 -07:00
mprotect.c mm: cleanup: remove #ifdef CONFIG_MIGRATION 2009-01-06 15:59:00 -08:00
mremap.c mm: update my address 2009-01-05 17:44:42 -08:00
msync.c add a vfs_fsync helper 2009-01-05 11:54:28 -05:00
nommu.c inode->i_op is never NULL 2009-01-05 11:54:28 -05:00
oom_kill.c oom: print triggering task's cpuset and mems allowed 2009-01-06 15:58:59 -08:00
page_alloc.c badpage: replace page_remove_rmap Eeek and BUG 2009-01-06 15:59:07 -08:00
page_cgroup.c mm: make init_section_page_cgroup() static 2009-01-06 15:59:04 -08:00
page_io.c mm: try_to_free_swap replaces remove_exclusive_swap_page 2009-01-06 15:59:03 -08:00
page_isolation.c memory hotplug: fix page_zone() calculation in test_pages_isolated() 2008-11-06 15:41:19 -08:00
page-writeback.c mm: add dirty_background_bytes and dirty_bytes sysctls 2009-01-06 15:59:03 -08:00
pagewalk.c pagemap: pass mm into pagewalkers 2008-06-12 18:05:41 -07:00
pdflush.c cpumask: convert mm/ 2009-01-01 10:12:29 +10:30
prio_tree.c spelling fixes: mm/ 2007-10-20 01:27:18 +02:00
quicklist.c mm: size of quicklists shouldn't be proportional to the number of CPUs 2008-09-02 19:21:38 -07:00
readahead.c vmscan: split LRU lists into anon & file sets 2008-10-20 08:50:25 -07:00
rmap.c badpage: replace page_remove_rmap Eeek and BUG 2009-01-06 15:59:07 -08:00
shmem_acl.c [PATCH] sanitize ->permission() prototype 2008-07-26 20:53:14 -04:00
shmem.c mm: don't mark_page_accessed in shmem_fault 2009-01-06 15:58:58 -08:00
slab.c cpumask: convert mm/ 2009-01-01 10:12:29 +10:30
slob.c slob: do not pass the SLAB flags as GFP in kmem_cache_create() 2008-12-15 16:27:06 -08:00
slub.c cpumask: convert mm/ 2009-01-01 10:12:29 +10:30
sparse-vmemmap.c vmemmap: warn about page_structs with remote distance 2008-11-06 15:41:19 -08:00
sparse.c meminit section warnings 2008-11-30 10:03:35 -08:00
swap_state.c mm: remove gfp_mask from add_to_swap 2009-01-06 15:59:04 -08:00
swap.c mm: try_to_free_swap replaces remove_exclusive_swap_page 2009-01-06 15:59:03 -08:00
swapfile.c swapfile: let others seed random 2009-01-06 15:59:06 -08:00
thrash.c Bug in mm/thrash.c function grab_swap_token() 2007-05-11 08:29:32 -07:00
tiny-shmem.c Export tiny shmem_file_setup for DRM-GEM 2008-10-20 16:17:42 -07:00
truncate.c mmap: handle mlocked pages during map, remap, unmap 2008-10-20 08:52:31 -07:00
util.c mm: Make generic weak get_user_pages_fast and EXPORT_GPL it 2008-08-12 17:52:53 +10:00
vmalloc.c mm: vmalloc make lazy unmapping configurable 2009-01-06 15:59:01 -08:00
vmscan.c mm: kill zone_is_near_oom() 2009-01-06 15:59:06 -08:00
vmstat.c cpumask: convert mm/ 2009-01-01 10:12:29 +10:30