On Wed, 2019-11-06 at 17:43 +0800, zhangyi (F) wrote: > During backport 1e2e547a93a "do d_instantiate/unlock_new_inode > combinations safely", there was a error instantiating sequence of > attaching dentry to inode and calling security_d_instantiate(). > > Before commit ce23e640133 "->getxattr(): pass dentry and inode as > separate arguments" and b96809173e9 "security_d_instantiate(): move to > the point prior to attaching dentry to inode", security_d_instantiate() > should be called beind __d_instantiate(), otherwise it will trigger > below problem when CONFIG_SECURITY_SMACK on ext4 was enabled because > d_inode(dentry) used by ->getxattr() is NULL before __d_instantiate() > instantiate inode. Thanks, I've queued this up for 3.16. Ben. > [ 31.858026] BUG: unable to handle kernel paging request at ffffffffffffff70 > ... > [ 31.882024] Call Trace: > [ 31.882378] [<ffffffffa347f75c>] ext4_xattr_get+0x8c/0x3e0 > [ 31.883195] [<ffffffffa3489454>] ext4_xattr_security_get+0x24/0x40 > [ 31.884086] [<ffffffffa336a56b>] generic_getxattr+0x5b/0x90 > [ 31.884907] [<ffffffffa3700514>] smk_fetch+0xb4/0x150 > [ 31.885634] [<ffffffffa3700772>] smack_d_instantiate+0x1c2/0x550 > [ 31.886508] [<ffffffffa36f9a5a>] security_d_instantiate+0x3a/0x80 > [ 31.887389] [<ffffffffa3353b26>] d_instantiate_new+0x36/0x130 > [ 31.888223] [<ffffffffa342b1ef>] ext4_mkdir+0x4af/0x6a0 > [ 31.888928] [<ffffffffa3343470>] vfs_mkdir+0x100/0x280 > [ 31.889536] [<ffffffffa334b086>] SyS_mkdir+0xb6/0x170 > [ 31.890255] [<ffffffffa307c855>] ? trace_do_page_fault+0x95/0x2b0 > [ 31.891134] [<ffffffffa3c5e078>] entry_SYSCALL_64_fastpath+0x18/0x73 > > Cc: <stable@xxxxxxxxxxxxxxx> # 3.16, 4.4 > Signed-off-by: zhangyi (F) <yi.zhang@xxxxxxxxxx> > --- > fs/dcache.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/dcache.c b/fs/dcache.c > index 5a1c36dc5d65..baa00718d8d1 100644 > --- a/fs/dcache.c > +++ b/fs/dcache.c > @@ -1900,7 +1900,6 @@ void d_instantiate_new(struct dentry *entry, struct inode *inode) > BUG_ON(!hlist_unhashed(&entry->d_u.d_alias)); > BUG_ON(!inode); > lockdep_annotate_inode_mutex_key(inode); > - security_d_instantiate(entry, inode); > spin_lock(&inode->i_lock); > __d_instantiate(entry, inode); > WARN_ON(!(inode->i_state & I_NEW)); > @@ -1908,6 +1907,7 @@ void d_instantiate_new(struct dentry *entry, struct inode *inode) > smp_mb(); > wake_up_bit(&inode->i_state, __I_NEW); > spin_unlock(&inode->i_lock); > + security_d_instantiate(entry, inode); > } > EXPORT_SYMBOL(d_instantiate_new); > -- Ben Hutchings If the facts do not conform to your theory, they must be disposed of.
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