Messages in this thread Patch in this message | | | Date | Tue, 24 Aug 2010 15:44:24 -0700 | From | Greg KH <> | Subject | [019/114] nilfs2: fix list corruption after ifile creation failure |
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2.6.35-stable review patch. If anyone has any objections, please let us know.
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From: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
commit af4e36318edb848fcc0a8d5f75000ca00cdc7595 upstream.
If nilfs_attach_checkpoint() gets a memory allocation failure during creation of ifile, it will return without removing nilfs_sb_info struct from ns_supers list. When a concurrently mounted snapshot is unmounted or another new snapshot is mounted after that, this causes kernel oops as below:
> BUG: unable to handle kernel NULL pointer dereference at (null) > IP: [<f83662ff>] nilfs_find_sbinfo+0x74/0xa4 [nilfs2] > *pde = 00000000 > Oops: 0000 [#1] SMP <snip> > Call Trace: > [<f835dc29>] ? nilfs_get_sb+0x165/0x532 [nilfs2] > [<c1173c87>] ? ida_get_new_above+0x16d/0x187 > [<c109a7f8>] ? alloc_vfsmnt+0x7e/0x10a > [<c1070790>] ? kstrdup+0x2c/0x40 > [<c1089041>] ? vfs_kern_mount+0x96/0x14e > [<c108913d>] ? do_kern_mount+0x32/0xbd > [<c109b331>] ? do_mount+0x642/0x6a1 > [<c101a415>] ? do_page_fault+0x0/0x2d1 > [<c1099c00>] ? copy_mount_options+0x80/0xe2 > [<c10705d8>] ? strndup_user+0x48/0x67 > [<c109b3f1>] ? sys_mount+0x61/0x90 > [<c10027cc>] ? sysenter_do_call+0x12/0x22
This fixes the problem.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Tested-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/nilfs2/super.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/fs/nilfs2/super.c +++ b/fs/nilfs2/super.c @@ -336,9 +336,10 @@ int nilfs_attach_checkpoint(struct nilfs list_add(&sbi->s_list, &nilfs->ns_supers); up_write(&nilfs->ns_super_sem); + err = -ENOMEM; sbi->s_ifile = nilfs_ifile_new(sbi, nilfs->ns_inode_size); if (!sbi->s_ifile) - return -ENOMEM; + goto delist; down_read(&nilfs->ns_segctor_sem); err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp, @@ -369,6 +370,7 @@ int nilfs_attach_checkpoint(struct nilfs nilfs_mdt_destroy(sbi->s_ifile); sbi->s_ifile = NULL; + delist: down_write(&nilfs->ns_super_sem); list_del_init(&sbi->s_list); up_write(&nilfs->ns_super_sem);
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