On Wed, Jul 15, 2015 at 03:33:58PM +0900, Joonsoo Kim wrote: > When I tested my new patches, I found that page pointer which is used > for setting page_owner information is changed. This is because page > pointer is used to set new migratetype in loop. After this work, > page pointer could be out of bound. If this wrong pointer is used for > page_owner, access violation happens. Below is error message that I got. > > [ 6175.025217] BUG: unable to handle kernel paging request at 0000000000b00018 > [ 6175.026400] IP: [<ffffffff81025f30>] save_stack_address+0x30/0x40 > [ 6175.027341] PGD 1af2d067 PUD 166e0067 PMD 0 > [ 6175.028129] Oops: 0002 [#1] SMP > snip... > [ 6175.055349] Call Trace: > [ 6175.055780] [<ffffffff81018c0f>] print_context_stack+0xcf/0x100 > [ 6175.056794] [<ffffffff810f8552>] ? __module_text_address+0x12/0x70 > [ 6175.057848] [<ffffffff810177cf>] dump_trace+0x15f/0x320 > [ 6175.058751] [<ffffffff8106b140>] ? do_flush_tlb_all+0x50/0x50 > [ 6175.059732] [<ffffffff810f5529>] ? smp_call_function_single+0xb9/0x120 > [ 6175.060856] [<ffffffff81025e3f>] save_stack_trace+0x2f/0x50 > [ 6175.061812] [<ffffffff811e3366>] __set_page_owner+0x46/0x70 > [ 6175.062774] [<ffffffff8117bd47>] __isolate_free_page+0x1f7/0x210 > [ 6175.063804] [<ffffffff8117bd81>] split_free_page+0x21/0xb0 > [ 6175.064757] [<ffffffff8119aa82>] isolate_freepages_block+0x1e2/0x410 > [ 6175.065855] [<ffffffff8119b53d>] compaction_alloc+0x22d/0x2d0 > [ 6175.066850] [<ffffffff811d3779>] migrate_pages+0x289/0x8b0 > [ 6175.067798] [<ffffffff8119c16a>] ? isolate_migratepages_block+0x28a/0x6e0 > [ 6175.068960] [<ffffffff8119a000>] ? kmalloc_slab+0xa0/0xa0 > [ 6175.069892] [<ffffffff8119b310>] ? ftrace_raw_event_mm_compaction_deplete_template+0xc0/0xc0 > [ 6175.071327] [<ffffffff8119ce49>] compact_zone+0x409/0x880 > [ 6175.072261] [<ffffffff8119d32d>] compact_zone_order+0x6d/0x90 > [ 6175.073250] [<ffffffff8119d5d0>] try_to_compact_pages+0x110/0x210 > [ 6175.074297] [<ffffffff8176e9e8>] __alloc_pages_direct_compact+0x3d/0xe6 > [ 6175.075427] [<ffffffff8117d42d>] __alloc_pages_nodemask+0x6cd/0x9a0 > [ 6175.076517] [<ffffffff811c2bf1>] alloc_pages_current+0x91/0x100 > [ 6175.077545] [<ffffffff811e7216>] runtest_store+0x296/0xa50 > [ 6175.078497] [<ffffffff813a553c>] ? simple_strtoull+0x2c/0x50 > [ 6175.079465] [<ffffffff812130bd>] simple_attr_write+0xbd/0xe0 > [ 6175.080458] [<ffffffff811eb038>] __vfs_write+0x28/0xf0 > [ 6175.081349] [<ffffffff811edc39>] ? __sb_start_write+0x49/0xf0 > [ 6175.082345] [<ffffffff8130fe25>] ? security_file_permission+0x45/0xd0 > [ 6175.083453] [<ffffffff811eb729>] vfs_write+0xa9/0x1b0 > [ 6175.084334] [<ffffffff811ec4f6>] SyS_write+0x46/0xb0 > [ 6175.085196] [<ffffffff81172803>] ? context_tracking_user_enter+0x13/0x20 > [ 6175.086339] [<ffffffff81024c55>] ? syscall_trace_leave+0xa5/0x120 > [ 6175.087389] [<ffffffff81779472>] system_call_fastpath+0x16/0x75 > > This patch fixes this error by moving up set_page_owner(). > > Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Acked-by: Minchan Kim <minchan@xxxxxxxxxx> -stable material? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>