On Mon, Mar 14, 2011 at 12:20:52PM -0700, Hugh Dickins wrote: > When testing something else on 2.6.38-rc8 last night, > I hit this x86_64 stack overflow. I've never had one before, > it seems worth reporting. kdb was in, I jotted it down by hand > (the notifier part of it will be notifying kdb of the fault). > CONFIG_DEBUG_STACK_OVERFLOW and DEBUG_STACK_USAGE were not set. > > I should disclose that I have a hack in which may make my stack > frames slightly larger than they should be: check against yours. > So it may not be an overflow for anyone else, but still a trace > to worry about. Here's the trace translated to the stack space used by each function. There are a few piggy ext4 functions that we can try to shrink, but the real problem is just how deep the whole stack is getting. >From the syscall to the lowest-level ext4 function is 3712 bytes, and everything from there to the schedule() which then triggered the GPF was another 3728 of stack space.... - Ted 240 schedule+0x25a 368 io_schedule+0x35 32 get_request_wait+0xc6 160 __make_request+0x36d 112 generic_make_request+0x2f2 208 submit_bio+0xe1 144 swap_writepage+0xa3 80 pageout+0x151 128 shrink_page_list+0x2db 176 shrink_inactive_list+0x2d3 256 shrink_zone+0x17d 224 shrink_zones+0x0xa3 128 do_try_to_free_pages+0x87 144 try_to_free_mem_cgroup_pages+0x8e 112 mem_cgroup_hierarchical_reclaim+0x220 176 mem_cgroup_do_charge+0xdc 128 __mem_cgroup_try_charge+0x19c 128 mem_cgroup_charge_common+0xa8 128 mem_cgroup_cache_charge+0x19a 128 add_to_page_cache_locked+0x57 96 add_to_page_cache_lru+0x3e 80 find_or_create_page+0x69 112 grow_dev_page+0x4a 96 grow_buffers+0x41 64 __getblk_slow+0xd7 80 __getblk+0x44 80 __ext4_get_inode_loc+0x12c 176 ext4_get_inode_loc+0x30 48 ext4_reserve_inode_write+0x21 80 ext4_mark_inode_dirty+0x3b 160 ext4_dirty_inode+0x3e 64 __mark_inode_dirty+0x32 80 linux/fs.h mark_inode_dirty 0 linux/quotaops.h dquot_alloc_space 0 linux/quotaops.h dquot_alloc_block 0 ext4_mb_new_blocks+0xc2 144 ext4_alloc_blocks+0x189 208 ext4_alloc_branch+0x73 208 ext4_ind_map_blocks+0x148 272 ext4_map_blocks+0x148 112 ext4_getblk+0x5f 144 ext4_bread+0x36 96 ext4_append+0x52 96 do_split+0x5b 224 ext4_dx_add_entry+0x4b4 304 ext4_add_entry+0x7c 176 ext4_add_nondir+0x2e 80 ext4_create+0xf5 144 vfs_create+0x83 96 __open_namei_create+0x59 96 do_last+0x13b 112 do_filp_open+0x2ae 384 do_sys_open+0x72 128 sys_open+0x27 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>