Date: Fri, 27 Dec 2013 16:13:42 GMT From: Greg Becker <beckerg@netapp.com> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/185232: Kernel page fault in jailed() via vn_stat() when using uio_td from nfsrv_read() Message-ID: <201312271613.rBRGDgN8068938@oldred.freebsd.org> Resent-Message-ID: <201312271620.rBRGK0bc069811@freefall.freebsd.org>
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>Number: 185232 >Category: kern >Synopsis: Kernel page fault in jailed() via vn_stat() when using uio_td from nfsrv_read() >Confidential: no >Severity: non-critical >Priority: low >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Fri Dec 27 16:20:00 UTC 2013 >Closed-Date: >Last-Modified: >Originator: Greg Becker >Release: 9.2 >Organization: NetApp >Environment: FreeBSD perf-filer-1.stl.netapp.com 9.2-STABLE FreeBSD 9.2-STABLE #69 r259677M: Fri Dec 27 06:15:18 CST 2013 beckerg@perf-filer-1.stl.netapp.com:/usr/obj/usr/src/sys/PERFFILER1 amd64 >Description: I'm using a custom nullfs that calls vn_stat() from my null_read() function. The problem is, nfsrv_read() doesn't set uio_td, so my null_read() function gets whatever was on the caller's stack. >How-To-Repeat: >Fix: Either don't use uio_td when being called from nfssrv_read(), or set uio_td to NULL in nfssrv_read(). Patch attached with submission follows: Index: sys/nfsserver/nfs_serv.c =================================================================== --- sys/nfsserver/nfs_serv.c (revision 259677) +++ sys/nfsserver/nfs_serv.c (working copy) @@ -965,6 +965,7 @@ uiop->uio_resid = len; uiop->uio_rw = UIO_READ; uiop->uio_segflg = UIO_SYSSPACE; + uiop->uio_td = NULL; nh = nfsrv_sequential_heuristic(uiop, vp); ioflag |= nh->nh_seqcount << IO_SEQSHIFT; error = VOP_READ(vp, uiop, IO_NODELOCKED | ioflag, cred); >Release-Note: >Audit-Trail: >Unformatted:
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