android_kernel_samsung_msm8976/mm
Jan Kara 07d6db9281 mm: make sendfile(2) killable
commit 296291cdd1629c308114504b850dc343eabc2782 upstream.

Currently a simple program below issues a sendfile(2) system call which
takes about 62 days to complete in my test KVM instance.

        int fd;
        off_t off = 0;

        fd = open("file", O_RDWR | O_TRUNC | O_SYNC | O_CREAT, 0644);
        ftruncate(fd, 2);
        lseek(fd, 0, SEEK_END);
        sendfile(fd, fd, &off, 0xfffffff);

Now you should not ask kernel to do a stupid stuff like copying 256MB in
2-byte chunks and call fsync(2) after each chunk but if you do, sysadmin
should have a way to stop you.

We actually do have a check for fatal_signal_pending() in
generic_perform_write() which triggers in this path however because we
always succeed in writing something before the check is done, we return
value > 0 from generic_perform_write() and thus the information about
signal gets lost.

Fix the problem by doing the signal check before writing anything.  That
way generic_perform_write() returns -EINTR, the error gets propagated up
and the sendfile loop terminates early.

Signed-off-by: Jan Kara <jack@suse.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-11-09 10:12:58 -08:00
..
backing-dev.c bdi: avoid oops on device removal 2014-04-26 17:15:35 -07:00
balloon_compaction.c
bootmem.c
bounce.c
cleancache.c
compaction.c mm/compaction: fix wrong order check in compact_finished() 2015-03-18 13:22:28 +01:00
debug-pagealloc.c
dmapool.c
fadvise.c
failslab.c
filemap.c mm: make sendfile(2) killable 2015-11-09 10:12:58 -08:00
filemap_xip.c
fremap.c mm: fix use-after-free in sys_remap_file_pages 2014-01-09 12:24:24 -08:00
frontswap.c mm: frontswap: invalidate expired data on a dup-store failure 2014-12-16 09:09:41 -08:00
highmem.c
huge_memory.c mm: numa: Do not mark PTEs pte_numa when splitting huge pages 2014-10-09 12:18:42 -07:00
hugetlb.c mm: hugetlbfs: skip shared VMAs when unmapping private pages to satisfy a fault 2015-10-22 14:37:50 -07:00
hugetlb_cgroup.c
hwpoison-inject.c
init-mm.c
internal.h
interval_tree.c
Kconfig
Kconfig.debug
kmemcheck.c
kmemleak-test.c
kmemleak.c
ksm.c vm: add VM_FAULT_SIGSEGV handling support 2015-04-29 10:34:00 +02:00
maccess.c
madvise.c
Makefile
memblock.c
memcontrol.c mm: memcg: handle non-error OOM situations more gracefully 2014-11-21 09:22:56 -08:00
memory-failure.c mm/hwpoison: fix page refcount of unknown non LRU page 2015-09-13 09:07:59 -07:00
memory.c mm: avoid setting up anonymous pages into file mapping 2015-08-10 12:20:29 -07:00
memory_hotplug.c mm/memory_hotplug.c: set zone->wait_table to null after freeing it 2015-06-22 16:55:54 -07:00
mempolicy.c cpuset,mempolicy: fix sleeping function called from invalid context 2014-07-17 15:58:00 -07:00
mempool.c
migrate.c mm: numa: avoid unnecessary work on the failure path 2014-01-09 12:24:23 -08:00
mincore.c
mlock.c mm: try_to_unmap_cluster() should lock_page() before mlocking 2014-05-06 07:55:32 -07:00
mm_init.c
mmap.c mm/mmap.c: fix arithmetic overflow in __vm_enough_memory() 2015-03-18 13:22:27 +01:00
mmu_context.c
mmu_notifier.c
mmzone.c
mprotect.c mm: fix TLB flush race between migration, and change_protection_range 2014-01-09 12:24:23 -08:00
mremap.c mm, thp: close race between mremap() and split_huge_page() 2014-06-07 13:25:31 -07:00
msync.c
nobootmem.c
nommu.c mm/nommu.c: fix arithmetic overflow in __vm_enough_memory() 2015-03-18 13:22:28 +01:00
oom_kill.c mm: memcg: handle non-error OOM situations more gracefully 2014-11-21 09:22:56 -08:00
page-writeback.c writeback: fix possible underflow in write bandwidth calculation 2015-04-19 10:10:48 +02:00
page_alloc.c OOM, PM: OOM killed task shouldn't escape PM suspend 2014-11-14 08:47:58 -08:00
page_cgroup.c cgroup/kmemleak: add kmemleak_free() for cgroup deallocations. 2014-11-14 08:47:59 -08:00
page_io.c
page_isolation.c
pagewalk.c mm: pagewalk: call pte_hole() for VM_PFNMAP during walk_page_range 2015-02-11 14:48:16 +08:00
percpu-km.c
percpu-vm.c percpu: perform tlb flush after pcpu_map_pages() failure 2014-10-05 14:54:13 -07:00
percpu.c Revert "percpu: free percpu allocation info for uniprocessor system" 2014-11-14 08:47:53 -08:00
pgtable-generic.c mm: fix TLB flush race between migration, and change_protection_range 2014-01-09 12:24:23 -08:00
process_vm_access.c
quicklist.c
readahead.c
rmap.c mm: fix sleeping function warning from __put_anon_vma 2014-06-30 20:09:42 -07:00
shmem.c shmem: fix nlink for rename overwrite directory 2014-10-05 14:54:11 -07:00
slab.c
slab.h
slab_common.c slab_common: fix the check for duplicate slab names 2014-07-31 12:53:50 -07:00
slob.c
slub.c slub: Fix calculation of cpu slabs 2014-02-13 13:48:00 -08:00
sparse-vmemmap.c
sparse.c
swap.c mm: close PageTail race 2014-04-03 12:01:05 -07:00
swap_state.c
swapfile.c
truncate.c mm: Remove false WARN_ON from pagecache_isize_extended() 2014-11-14 08:48:00 -08:00
util.c vm_is_stack: use for_each_thread() rather then buggy while_each_thread() 2014-10-05 14:54:16 -07:00
vmalloc.c
vmpressure.c
vmscan.c vmscan: fix increasing nr_isolated incurred by putback unevictable pages 2015-10-01 12:07:32 +02:00
vmstat.c