From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with SMTP id 1AEC46B01B2 for ; Sat, 22 May 2010 12:25:24 -0400 (EDT) Message-ID: <4BF8056E.8080900@sandeen.net> Date: Sat, 22 May 2010 11:25:18 -0500 From: Eric Sandeen MIME-Version: 1.0 Subject: [PATCH (resend)] xfs: don't allow recursion into fs under write_begin Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: xfs-oss , "linux-fsdevel@vger.kernel.org" , linux-mm@kvack.org Cc: Michael Monnerie List-ID: Michael Monnerie reported this fantastic stack overflow: [21877.948005] BUG: scheduling while atomic: rsync/2345/0xffff8800 [21877.948005] Modules linked in: af_packet nfs lockd fscache nfs_acl auth_rpcgss sunrpc ipv6 ramzswap xvmalloc lzo_decompress lzo_compress loop dm_mod reiserfs xfs exportfs xennet xenblk cdrom [21877.948005] Pid: 2345, comm: rsync Not tainted 2.6.31.12-0.2-xen #1 [21877.948005] Call Trace: [21877.949649] [] try_stack_unwind+0x189/0x1b0 [21877.949659] [] dump_trace+0xa6/0x1e0 [21877.949666] [] show_trace_log_lvl+0x64/0x90 [21877.949676] [] show_trace+0x23/0x40 [21877.949684] [] dump_stack+0x81/0x9e [21877.949695] [] __schedule_bug+0x78/0x90 [21877.949702] [] thread_return+0x1d7/0x3fb [21877.949709] [] schedule_timeout+0x195/0x200 [21877.949717] [] wait_for_common+0x10b/0x230 [21877.949726] [] wait_for_completion+0x2b/0x50 [21877.949768] [] xfs_buf_iowait+0x31/0x80 [xfs] [21877.949894] [] _xfs_buf_read+0x70/0x80 [xfs] [21877.949992] [] xfs_buf_read_flags+0x8b/0xd0 [xfs] [21877.950089] [] xfs_trans_read_buf+0x1e9/0x320 [xfs] [21877.950174] [] xfs_btree_read_buf_block+0x68/0xe0 [xfs] [21877.950232] [] xfs_btree_lookup_get_block+0x8e/0x110 [xfs] [21877.950281] [] xfs_btree_lookup+0xdf/0x4d0 [xfs] [21877.950329] [] xfs_alloc_lookup_eq+0x27/0x50 [xfs] [21877.950361] [] xfs_alloc_fixup_trees+0x249/0x370 [xfs] [21877.950397] [] xfs_alloc_ag_vextent_near+0x4e0/0x9a0 [xfs] [21877.950432] [] xfs_alloc_ag_vextent+0x105/0x160 [xfs] [21877.950471] [] xfs_alloc_vextent+0x3b4/0x4b0 [xfs] [21877.950504] [] xfs_bmbt_alloc_block+0xf8/0x210 [xfs] [21877.950550] [] xfs_btree_split+0xc7/0x720 [xfs] [21877.950597] [] xfs_btree_make_block_unfull+0x15c/0x1c0 [xfs] [21877.950643] [] xfs_btree_insrec+0x40f/0x5c0 [xfs] [21877.950689] [] xfs_btree_insert+0xa1/0x1b0 [xfs] [21877.950748] [] xfs_bmap_add_extent_delay_real+0x82e/0x12a0 [xfs] [21877.950787] [] xfs_bmap_add_extent+0x424/0x450 [xfs] [21877.950833] [] xfs_bmapi+0xda3/0x1320 [xfs] [21877.950879] [] xfs_iomap_write_allocate+0x1d8/0x3f0 [xfs] [21877.950953] [] xfs_iomap+0x2c9/0x300 [xfs] [21877.951021] [] xfs_map_blocks+0x38/0x60 [xfs] [21877.951108] [] xfs_page_state_convert+0x3fa/0x720 [xfs] [21877.951204] [] xfs_vm_writepage+0x84/0x160 [xfs] [21877.951301] [] pageout+0x143/0x2b0 [21877.951308] [] shrink_page_list+0x26e/0x650 [21877.951314] [] shrink_inactive_list+0x2d3/0x7c0 [21877.951320] [] shrink_list+0x5b/0x110 [21877.951325] [] shrink_zone+0x171/0x250 [21877.951330] [] shrink_zones+0x83/0x120 [21877.951336] [] do_try_to_free_pages+0x9e/0x380 [21877.951342] [] try_to_free_pages+0x77/0xa0 [21877.951349] [] __alloc_pages_slowpath+0x2d3/0x5c0 [21877.951355] [] __alloc_pages_nodemask+0x151/0x160 [21877.951362] [] __page_cache_alloc+0x27/0x50 [21877.951368] [] grab_cache_page_write_begin+0x9a/0xe0 [21877.951376] [] block_write_begin+0xae/0x120 [21877.951396] [] xfs_vm_write_begin+0x34/0x50 [xfs] [21877.951482] [] generic_perform_write+0xc1/0x1f0 [21877.951489] [] generic_file_buffered_write+0x90/0x160 [21877.951512] [] xfs_write+0x521/0xb60 [xfs] [21877.951624] [] xfs_file_aio_write+0x70/0xa0 [xfs] [21877.951711] [] do_sync_write+0x102/0x160 [21877.951718] [] vfs_write+0xd8/0x1c0 [21877.951723] [] sys_write+0x5b/0xa0 [21877.951729] [] system_call_fastpath+0x16/0x1b [21877.951736] [<00007fc41b0fab10>] 0x7fc41b0fab10 [21877.951750] BUG: unable to handle kernel paging request at 0000000108743280 [21877.951755] IP: [] dequeue_task+0x72/0x110 [21877.951766] PGD 31c6f067 PUD 0 [21877.951770] Thread overran stack, or stack corrupted I don't think we can afford to let write_begin recurse into the fs, so we can set AOP_FLAG_NOFS ... is this too big a hammer? Reported-by: Michael Monnerie Signed-off-by: Eric Sandeen --- (resend with linux-fsdevel and linux-mm per Christoph's request) diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c index 57c3827..3fb2cc8 100644 --- a/fs/xfs/linux-2.6/xfs_aops.c +++ b/fs/xfs/linux-2.6/xfs_aops.c @@ -1678,6 +1678,8 @@ xfs_vm_write_begin( void **fsdata) { *pagep = NULL; + /* can't afford to recurse into fs due to stack reasons */ + flags |= AOP_FLAG_NOFS; return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata, xfs_get_blocks); } -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org