Re: why does index in truncate_inode_pages_range() grows so much ?

["Toralf Förster" <toralf.foerster@gmx.de>]

On 12/04/2013 02:06 PM, Jan Kara wrote:
>   One idea: Can you add
> WARN_ON(offset > 10000000);
>   into mm/filemap.c:add_to_page_cache_locked() ? That should tell us
> whether someone is indeed inserting pages with strange indices into page
> cache or if page->index got somehow corrupted.
> 
>  								Honza
>> > 

With this diff :

diff --git a/mm/filemap.c b/mm/filemap.c
index b7749a9..e95d90c 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -463,6 +463,7 @@ int add_to_page_cache_locked(struct page *page, struct address_space *mapping,

        VM_BUG_ON(!PageLocked(page));
        VM_BUG_ON(PageSwapBacked(page));
+       WARN_ON(offset > 10000000);

        error = mem_cgroup_cache_charge(page, current->mm,
                                        gfp_mask & GFP_RECLAIM_MASK);



I do get such things :

Dec  7 18:01:29 trinity tfoerste: M=1
Dec  7 18:01:36 trinity kernel: type=1006 audit(1386435689.994:3): pid=1260 uid=0 old auid=4294967295 new auid=1000 old ses=4294967295 new ses=2 res=1
Dec  7 18:01:42 trinity kernel: warning: process `trinity-child0' used the deprecated sysctl system call with
Dec  7 18:01:42 trinity kernel: VFS: Warning: trinity-child0 using old stat() call. Recompile your binary.
Dec  7 18:01:44 trinity kernel: ------------[ cut here ]------------
Dec  7 18:01:44 trinity kernel: WARNING: CPU: 0 PID: 1478 at mm/filemap.c:466 add_to_page_cache_locked+0x34/0xf0()
Dec  7 18:01:44 trinity kernel: CPU: 0 PID: 1478 Comm: trinity-child0 Not tainted 3.13.0-rc3-dirty #16
Dec  7 18:01:44 trinity kernel: Stack:
Dec  7 18:01:44 trinity kernel: 084c0773 084c0773 49be7ca8 00000004 085d0547 49be0000 00000000 084ce2d4
Dec  7 18:01:44 trinity kernel: 49be7cb8 08425f7f 00000000 00000000 49be7cf0 0807d43b 084cc244 00000000
Dec  7 18:01:44 trinity kernel: 000005c6 084ce2d4 000001d2 080cb714 080cb714 000001d2 49be7cfc 0b811b60
Dec  7 18:01:44 trinity kernel: Call Trace:
Dec  7 18:01:44 trinity kernel: [<08425f7f>] dump_stack+0x26/0x28
Dec  7 18:01:44 trinity kernel: [<0807d43b>] warn_slowpath_common+0x7b/0xa0
Dec  7 18:01:44 trinity kernel: [<080cb714>] ? add_to_page_cache_locked+0x34/0xf0
Dec  7 18:01:44 trinity kernel: [<080cb714>] ? add_to_page_cache_locked+0x34/0xf0
Dec  7 18:01:44 trinity kernel: [<0807d503>] warn_slowpath_null+0x23/0x30
Dec  7 18:01:44 trinity kernel: [<080cb714>] add_to_page_cache_locked+0x34/0xf0
Dec  7 18:01:44 trinity kernel: [<080cb7fb>] add_to_page_cache_lru+0x2b/0x50
Dec  7 18:01:44 trinity kernel: [<080cd38b>] generic_file_aio_read+0x57b/0x710
Dec  7 18:01:44 trinity kernel: [<081035ee>] do_sync_read+0x6e/0xa0
Dec  7 18:01:44 trinity kernel: [<08104199>] vfs_read+0xa9/0x180
Dec  7 18:01:44 trinity kernel: [<081047cc>] SyS_pread64+0x6c/0xa0
Dec  7 18:01:44 trinity kernel: [<08062a94>] handle_syscall+0x64/0x80
Dec  7 18:01:44 trinity kernel: [<083d8831>] ? ptrace+0x31/0x80
Dec  7 18:01:44 trinity kernel: [<0807a072>] ? get_fp_registers+0x22/0x40
Dec  7 18:01:44 trinity kernel: [<080750f5>] userspace+0x475/0x5f0
Dec  7 18:01:44 trinity kernel: [<083d8831>] ? ptrace+0x31/0x80
Dec  7 18:01:44 trinity kernel: [<0807a5d6>] ? os_set_thread_area+0x26/0x40
Dec  7 18:01:44 trinity kernel: [<080795a0>] ? do_set_thread_area+0x20/0x50
Dec  7 18:01:44 trinity kernel: [<08079718>] ? arch_switch_tls+0xb8/0x100
Dec  7 18:01:44 trinity kernel: [<0805f750>] fork_handler+0x60/0x70
Dec  7 18:01:44 trinity kernel:
Dec  7 18:01:44 trinity kernel: ---[ end trace 7ce562aa9f07d154 ]---








Just FWIW in addition I do have these diffs :

diff --git a/mm/truncate.c b/mm/truncate.c
index 353b683..41eecba 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -244,6 +244,11 @@ void truncate_inode_pages_range(struct address_space *mapping,
                for (i = 0; i < pagevec_count(&pvec); i++) {
                        struct page *page = pvec.pages[i];

+                       if (index > 1000)       {
+                               printk (" page->index:%ld  ->flags:%lu  ->s_id:%s  ->i_no:%lu \n",
+                                       page->index , page->flags, page->mapping->host->i_sb->s_id, page->mapping->host->i_ino);
+                       }
+
                        /* We rely upon deletion not changing page->index */
                        index = page->index;
                        if (index >= end)
@@ -259,6 +264,9 @@ void truncate_inode_pages_range(struct address_space *mapping,
                        truncate_inode_page(mapping, page);
                        unlock_page(page);
                }
+               if (index > 1000)       {
+                       printk (" index:%lu  i:%i  start:%lu \n", index, i, start);
+               }
                pagevec_release(&pvec);
                mem_cgroup_uncharge_end();
                cond_resched();


producing these results :

Dec  7 18:00:59 trinity kernel: ubda: unknown partition table
Dec  7 18:00:59 trinity kernel: ubdb: unknown partition table
Dec  7 18:00:59 trinity kernel: Netdevice 0 (72:ef:3d:9f:c3:5a) :
Dec  7 18:00:59 trinity kernel: TUN/TAP backend -
Dec  7 18:00:59 trinity kernel: EXT4-fs (ubda): INFO: recovery required on readonly filesystem
Dec  7 18:00:59 trinity kernel: EXT4-fs (ubda): write access will be enabled during recovery
Dec  7 18:00:59 trinity kernel: EXT4-fs (ubda): orphan cleanup on readonly fs
Dec  7 18:00:59 trinity kernel: EXT4-fs (ubda): 1 orphan inode deleted
Dec  7 18:00:59 trinity kernel: EXT4-fs (ubda): recovery complete
Dec  7 18:00:59 trinity kernel: EXT4-fs (ubda): mounted filesystem with ordered data mode. Opts: (null)
Dec  7 18:00:59 trinity kernel: VFS: Mounted root (ext4 filesystem) readonly on device 98:0.
Dec  7 18:00:59 trinity kernel: devtmpfs: mounted
Dec  7 18:00:59 trinity kernel[537]: starting version 204
Dec  7 18:00:59 trinity kernel: random: nonblocking pool is initialized
Dec  7 18:00:59 trinity kernel: page->index:65503  ->flags:2092  ->s_id:bdev  ->i_no:0
Dec  7 18:00:59 trinity kernel: page->index:65504  ->flags:2152  ->s_id:bdev  ->i_no:0
Dec  7 18:00:59 trinity kernel: page->index:65520  ->flags:2092  ->s_id:bdev  ->i_no:0
Dec  7 18:00:59 trinity kernel: page->index:65528  ->flags:2092  ->s_id:bdev  ->i_no:0
Dec  7 18:00:59 trinity kernel: page->index:65534  ->flags:2152  ->s_id:bdev  ->i_no:0
Dec  7 18:00:59 trinity kernel: page->index:65535  ->flags:2156  ->s_id:bdev  ->i_no:0
Dec  7 18:00:59 trinity kernel: index:65535  i:13  start:0
Dec  7 18:00:59 trinity kernel: EXT4-fs (ubda): re-mounted. Opts: (null)
Dec  7 18:00:59 trinity kernel: [sched_delayed] sched: RT throttling activated
Dec  7 18:00:59 trinity kernel: bio: create slab <bio-1> at 1
Dec  7 18:00:59 trinity kernel: page->index:65503  ->flags:2152  ->s_id:bdev  ->i_no:0
Dec  7 18:00:59 trinity kernel: page->index:65504  ->flags:2156  ->s_id:bdev  ->i_no:0
Dec  7 18:00:59 trinity kernel: page->index:65520  ->flags:2152  ->s_id:bdev  ->i_no:0
Dec  7 18:00:59 trinity kernel: page->index:65528  ->flags:2152  ->s_id:bdev  ->i_no:0
Dec  7 18:00:59 trinity kernel: page->index:65534  ->flags:2156  ->s_id:bdev  ->i_no:0
Dec  7 18:00:59 trinity kernel: page->index:65535  ->flags:2156  ->s_id:bdev  ->i_no:0
Dec  7 18:00:59 trinity kernel: index:65535  i:13  start:0
Dec  7 18:00:59 trinity kernel: Adding 262140k swap on /dev/mapper/crypt-swap.  Priority:-1 extents:1 across:262140k FS
Dec  7 18:00:59 trinity kernel: type=1006 audit(1386435658.554:2): pid=1069 uid=0 old auid=4294967295 new auid=0 old ses=4294967295 new ses=1 res=1
Dec  7 18:00:59 trinity kernel: Virtual console 12 assigned device '/dev/pts/5'
Dec  7 18:01:00 trinity dhcpcd[1094]: version 5.6.4 starting
Dec  7 18:01:00 trinity dhcpcd[1094]: sit0: unsupported interface type 308, falling back to ethernet


-- 
MfG/Sincerely
Toralf Förster
pgp finger print:1A37 6F99 4A9D 026F 13E2 4DCF C4EA CDDE 0076 E94E