Re: [patch 4/9] fs, exportfs: Fix nil dereference if no s_export_op present
From: J. Bruce Fields <hidden>
Date: 2012-08-23 12:12:30
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On Thu, Aug 23, 2012 at 02:43:27PM +0400, Cyrill Gorcunov wrote:
If there is no s_export_op present in a target superblock we might have nil dereference.
Is that NULL dereference possible with current code, or is it a check you're adding to account for a new caller that you're about to add? I believe it's the latter, but this would be a good thing to make clear in the changelog. --b.
quoted hunk ↗ jump to hunk
Fix it with eplicit test if s_export_op is provided. Signed-off-by: Cyrill Gorcunov <redacted> CC: Pavel Emelyanov <redacted> CC: Al Viro <viro@ZenIV.linux.org.uk> CC: Alexey Dobriyan <redacted> CC: Andrew Morton <akpm@linux-foundation.org> CC: James Bottomley <redacted> CC: "Aneesh Kumar K.V" <redacted> CC: Alexey Dobriyan <redacted> CC: Matthew Helsley <redacted> CC: "J. Bruce Fields" <redacted> CC: "Aneesh Kumar K.V" <redacted> --- fs/exportfs/expfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: linux-2.6.git/fs/exportfs/expfs.c ===================================================================--- linux-2.6.git.orig/fs/exportfs/expfs.c +++ linux-2.6.git/fs/exportfs/expfs.c@@ -357,7 +357,7 @@ int exportfs_encode_fh(struct dentry *de */ parent = p->d_inode; } - if (nop->encode_fh) + if (nop && nop->encode_fh) error = nop->encode_fh(inode, fid->raw, max_len, parent); else error = export_encode_fh(inode, fid, max_len, parent);