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2012-05-07hfsplus: Fix potential buffer overflowsGreg Kroah-Hartman
commit 6f24f892871acc47b40dd594c63606a17c714f77 upstream. Commit ec81aecb2966 ("hfs: fix a potential buffer overflow") fixed a few potential buffer overflows in the hfs filesystem. But as Timo Warns pointed out, these changes also need to be made on the hfsplus filesystem as well. Reported-by: Timo Warns <warns@pre-sense.de> Acked-by: WANG Cong <amwang@redhat.com> Cc: Alexey Khoroshilov <khoroshilov@ispras.ru> Cc: Miklos Szeredi <mszeredi@suse.cz> Cc: Sage Weil <sage@newdream.net> Cc: Eugene Teo <eteo@redhat.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Dave Anderson <anderson@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-07exit_signal: simplify the "we have changed execution domain" logicOleg Nesterov
commit e636825346b36a07ccfc8e30946d52855e21f681 upstream. exit_notify() checks "tsk->self_exec_id != tsk->parent_exec_id" to handle the "we have changed execution domain" case. We can change do_thread() to always set ->exit_signal = SIGCHLD and remove this check to simplify the code. We could change setup_new_exec() instead, this looks more logical because it increments ->self_exec_id. But note that de_thread() already resets ->exit_signal if it changes the leader, let's keep both changes close to each other. Note that we change ->exit_signal lockless, this changes the rules. Thereafter ->exit_signal is not stable under tasklist but this is fine, the only possible change is OLDSIG -> SIGCHLD. This can race with eligible_child() but the race is harmless. We can race with reparent_leader() which changes our ->exit_signal in parallel, but it does the same change to SIGCHLD. The noticeable user-visible change is that the execing task is not "visible" to do_wait()->eligible_child(__WCLONE) right after exec. To me this looks more logical, and this is consistent with mt case. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-05-07autofs: make the autofsv5 packet file descriptor use a packetized pipeLinus Torvalds
commit 64f371bc3107e69efce563a3d0f0e6880de0d537 upstream. The autofs packet size has had a very unfortunate size problem on x86: because the alignment of 'u64' differs in 32-bit and 64-bit modes, and because the packet data was not 8-byte aligned, the size of the autofsv5 packet structure differed between 32-bit and 64-bit modes despite looking otherwise identical (300 vs 304 bytes respectively). We first fixed that up by making the 64-bit compat mode know about this problem in commit a32744d4abae ("autofs: work around unhappy compat problem on x86-64"), and that made a 32-bit 'systemd' work happily on a 64-bit kernel because everything then worked the same way as on a 32-bit kernel. But it turned out that 'automount' had actually known and worked around this problem in user space, so fixing the kernel to do the proper 32-bit compatibility handling actually *broke* 32-bit automount on a 64-bit kernel, because it knew that the packet sizes were wrong and expected those incorrect sizes. As a result, we ended up reverting that compatibility mode fix, and thus breaking systemd again, in commit fcbf94b9dedd. With both automount and systemd doing a single read() system call, and verifying that they get *exactly* the size they expect but using different sizes, it seemed that fixing one of them inevitably seemed to break the other. At one point, a patch I seriously considered applying from Michael Tokarev did a "strcmp()" to see if it was automount that was doing the operation. Ugly, ugly. However, a prettier solution exists now thanks to the packetized pipe mode. By marking the communication pipe as being packetized (by simply setting the O_DIRECT flag), we can always just write the bigger packet size, and if user-space does a smaller read, it will just get that partial end result and the extra alignment padding will simply be thrown away. This makes both automount and systemd happy, since they now get the size they asked for, and the kernel side of autofs simply no longer needs to care - it could pad out the packet arbitrarily. Of course, if there is some *other* user of autofs (please, please, please tell me it ain't so - and we haven't heard of any) that tries to read the packets with multiple writes, that other user will now be broken - the whole point of the packetized mode is that one system call gets exactly one packet, and you cannot read a packet in pieces. Tested-by: Michael Tokarev <mjt@tls.msk.ru> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: David Miller <davem@davemloft.net> Cc: Ian Kent <raven@themaw.net> Cc: Thomas Meyer <thomas@m3y3r.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-05-07pipes: add a "packetized pipe" mode for writingLinus Torvalds
commit 9883035ae7edef3ec62ad215611cb8e17d6a1a5d upstream. The actual internal pipe implementation is already really about individual packets (called "pipe buffers"), and this simply exposes that as a special packetized mode. When we are in the packetized mode (marked by O_DIRECT as suggested by Alan Cox), a write() on a pipe will not merge the new data with previous writes, so each write will get a pipe buffer of its own. The pipe buffer is then marked with the PIPE_BUF_FLAG_PACKET flag, which in turn will tell the reader side to break the read at that boundary (and throw away any partial packet contents that do not fit in the read buffer). End result: as long as you do writes less than PIPE_BUF in size (so that the pipe doesn't have to split them up), you can now treat the pipe as a packet interface, where each read() system call will read one packet at a time. You can just use a sufficiently big read buffer (PIPE_BUF is sufficient, since bigger than that doesn't guarantee atomicity anyway), and the return value of the read() will naturally give you the size of the packet. NOTE! We do not support zero-sized packets, and zero-sized reads and writes to a pipe continue to be no-ops. Also note that big packets will currently be split at write time, but that the size at which that happens is not really specified (except that it's bigger than PIPE_BUF). Currently that limit is the system page size, but we might want to explicitly support bigger packets some day. The main user for this is going to be the autofs packet interface, allowing us to stop having to care so deeply about exact packet sizes (which have had bugs with 32/64-bit compatibility modes). But user space can create packetized pipes with "pipe2(fd, O_DIRECT)", which will fail with an EINVAL on kernels that do not support this interface. Tested-by: Michael Tokarev <mjt@tls.msk.ru> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: David Miller <davem@davemloft.net> Cc: Ian Kent <raven@themaw.net> Cc: Thomas Meyer <thomas@m3y3r.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-05-07Revert "autofs: work around unhappy compat problem on x86-64"Linus Torvalds
commit fcbf94b9dedd2ce08e798a99aafc94fec8668161 upstream. This reverts commit a32744d4abae24572eff7269bc17895c41bd0085. While that commit was technically the right thing to do, and made the x86-64 compat mode work identically to native 32-bit mode (and thus fixing the problem with a 32-bit systemd install on a 64-bit kernel), it turns out that the automount binaries had workarounds for this compat problem. Now, the workarounds are disgusting: doing an "uname()" to find out the architecture of the kernel, and then comparing it for the 64-bit cases and fixing up the size of the read() in automount for those. And they were confused: it's not actually a generic 64-bit issue at all, it's very much tied to just x86-64, which has different alignment for an 'u64' in 64-bit mode than in 32-bit mode. But the end result is that fixing the compat layer actually breaks the case of a 32-bit automount on a x86-64 kernel. There are various approaches to fix this (including just doing a "strcmp()" on current->comm and comparing it to "automount"), but I think that I will do the one that teaches pipes about a special "packet mode", which will allow user space to not have to care too deeply about the padding at the end of the autofs packet. That change will make the compat workaround unnecessary, so let's revert it first, and get automount working again in compat mode. The packetized pipes will then fix autofs for systemd. Reported-and-requested-by: Michael Tokarev <mjt@tls.msk.ru> Cc: Ian Kent <raven@themaw.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-05-07NFS: put open context on error in nfs_flush_multiFred Isaman
commit 8ccd271f7a3a846ce6f85ead0760d9d12994a611 upstream. Signed-off-by: Fred Isaman <iisaman@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-05-07NFS: put open context on error in nfs_pagein_multiFred Isaman
commit 73fb7bc7c57d971b11f2e00536ac2d3e316e0609 upstream. Signed-off-by: Fred Isaman <iisaman@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-05-07NFSv4: Ensure that we check lock exclusive/shared type against open modesTrond Myklebust
commit 55725513b5ef9d462aa3e18527658a0362aaae83 upstream. Since we may be simulating flock() locks using NFS byte range locks, we can't rely on the VFS having checked the file open mode for us. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-05-07NFSv4: Ensure that the LOCK code sets exception->inodeTrond Myklebust
commit 05ffe24f5290dc095f98fbaf84afe51ef404ccc5 upstream. All callers of nfs4_handle_exception() that need to handle NFS4ERR_OPENMODE correctly should set exception->inode Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-05-07nfs: Enclose hostname in brackets when needed in nfs_do_root_mountJan Kara
commit 98a2139f4f4d7b5fcc3a54c7fddbe88612abed20 upstream. When hostname contains colon (e.g. when it is an IPv6 address) it needs to be enclosed in brackets to make parsing of NFS device string possible. Fix nfs_do_root_mount() to enclose hostname properly when needed. NFS code actually does not need this as it does not parse the string passed by nfs_do_root_mount() but the device string is exposed to userspace in /proc/mounts. CC: Josh Boyer <jwboyer@redhat.com> CC: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-27tcp: allow splice() to build full TSO packetsEric Dumazet
[ This combines upstream commit 2f53384424251c06038ae612e56231b96ab610ee and the follow-on bug fix commit 35f9c09fe9c72eb8ca2b8e89a593e1c151f28fc2 ] vmsplice()/splice(pipe, socket) call do_tcp_sendpages() one page at a time, adding at most 4096 bytes to an skb. (assuming PAGE_SIZE=4096) The call to tcp_push() at the end of do_tcp_sendpages() forces an immediate xmit when pipe is not already filled, and tso_fragment() try to split these skb to MSS multiples. 4096 bytes are usually split in a skb with 2 MSS, and a remaining sub-mss skb (assuming MTU=1500) This makes slow start suboptimal because many small frames are sent to qdisc/driver layers instead of big ones (constrained by cwnd and packets in flight of course) In fact, applications using sendmsg() (adding an additional memory copy) instead of vmsplice()/splice()/sendfile() are a bit faster because of this anomaly, especially if serving small files in environments with large initial [c]wnd. Call tcp_push() only if MSG_MORE is not set in the flags parameter. This bit is automatically provided by splice() internals but for the last page, or on all pages if user specified SPLICE_F_MORE splice() flag. In some workloads, this can reduce number of sent logical packets by an order of magnitude, making zero-copy TCP actually faster than one-copy :) Reported-by: Tom Herbert <therbert@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: H.K. Jerry Chu <hkchu@google.com> Cc: Maciej Żenczykowski <maze@google.com> Cc: Mahesh Bandewar <maheshb@google.com> Cc: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-27lockd: fix the endianness bugAl Viro
commit e847469bf77a1d339274074ed068d461f0c872bc upstream. comparing be32 values for < is not doing the right thing... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-27ocfs2: ->e_leaf_clusters endianness breakageAl Viro
commit 72094e43e3af5020510f920321d71f1798fa896d upstream. le16, not le32... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-27ocfs2: ->rl_count endianness breakageAl Viro
commit 28748b325dc2d730ccc312830a91c4ae0c0d9379 upstream. le16, not le32... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-27ocfs: ->rl_used breakage on big-endianAl Viro
commit e1bf4cc620fd143766ddfcee3b004a1d1bb34fd0 upstream. it's le16, not le32 or le64... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-27ocfs2: ->l_next_free_req breakage on big-endianAl Viro
commit 3a251f04fe97c3d335b745c98e4b377e3c3899f2 upstream. It's le16, not le32... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-27btrfs: btrfs_root_readonly() broken on big-endianAl Viro
commit 6ed3cf2cdfce4c9f1d73171bd3f27d9cb77b734e upstream. ->root_flags is __le64 and all accesses to it go through the helpers that do proper conversions. Except for btrfs_root_readonly(), which checks bit 0 as in host-endian... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-27nfsd: fix compose_entry_fh() failure exitsAl Viro
commit efe39651f08813180f37dc508d950fc7d92b29a8 upstream. Restore the original logics ("fail on mountpoints, negatives and in case of fh_compose() failures"). Since commit 8177e (nfsd: clean up readdirplus encoding) that got broken - rv = fh_compose(fhp, exp, dchild, &cd->fh); if (rv) goto out; if (!dchild->d_inode) goto out; rv = 0; out: is equivalent to rv = fh_compose(fhp, exp, dchild, &cd->fh); out: and the second check has no effect whatsoever... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Cc: "J. Bruce Fields" <bfields@fieldses.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-27nfsd: fix endianness breakage in TEST_STATEID handlingAl Viro
commit 02f5fde5df0ea930e70f93763dd48beff182b208 upstream. ->ts_id_status gets nfs errno, i.e. it's already big-endian; no need to apply htonl() to it. Broken by commit 174568 (NFSD: Added TEST_STATEID operation) last year... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Cc: "J. Bruce Fields" <bfields@fieldses.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-27nfsd: fix error values returned by nfsd4_lockt() when nfsd_open() failsAl Viro
commit 04da6e9d63427b2d0fd04766712200c250b3278f upstream. nfsd_open() already returns an NFS error value; only vfs_test_lock() result needs to be fed through nfserrno(). Broken by commit 55ef12 (nfsd: Ensure nfsv4 calls the underlying filesystem on LOCKT) three years ago... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-27nfsd: fix b0rken error value for setattr on read-only mountAl Viro
commit 96f6f98501196d46ce52c2697dd758d9300c63f5 upstream. ..._want_write() returns -EROFS on failure, _not_ an NFS error value. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-27ext4: fix endianness breakage in ext4_split_extent_at()Al Viro
commit af1584f570b19b0285e4402a0b54731495d31784 upstream. ->ee_len is __le16, so assigning cpu_to_le32() to it is going to do Bad Things(tm) on big-endian hosts... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Ted Ts'o <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-27jbd2: use GFP_NOFS for blkdev_issue_flushShaohua Li
commit 99aa78466777083255b876293e9e83dec7cd809a upstream. flush request is issued in transaction commit code path, so looks using GFP_KERNEL to allocate memory for flush request bio falls into the classic deadlock issue. I saw btrfs and dm get it right, but ext4, xfs and md are using GFP. Signed-off-by: Shaohua Li <shli@fusionio.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-22ext4: address scalability issue by removing extent cache statisticsTheodore Ts'o
commit 9cd70b347e9761ea2d2ac3d758c529a48a8193e6 upstream. Andi Kleen and Tim Chen have reported that under certain circumstances the extent cache statistics are causing scalability problems due to cache line bounces. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-22Revert "Btrfs: increase the global block reserve estimates"Chris Mason
commit 8e62c2de6e23e5c1fee04f59de51b54cc2868ca5 upstream. This reverts commit 5500cdbe14d7435e04f66ff3cfb8ecd8b8e44ebf. We've had a number of complaints of early enospc that bisect down to this patch. We'll hae to fix the reservations differently. Signed-off-by: Chris Mason <chris.mason@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-22Btrfs: fix regression in scrub path resolvingJan Schmidt
commit 7a3ae2f8c8c8432e65467b7fc84d5deab04061a0 upstream. In commit 4692cf58 we introduced new backref walking code for btrfs. This assumes we're searching live roots, which requires a transaction context. While scrubbing, however, we must not join a transaction because this could deadlock with the commit path. Additionally, what scrub really wants to do is resolving a logical address in the commit root it's currently checking. This patch adds support for logical to path resolving on commit roots and makes scrub use that. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net> Signed-off-by: Chris Mason <chris.mason@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-13Fix length of buffer copied in __nfs4_get_acl_uncachedSachin Prabhu
commit 20e0fa98b751facf9a1101edaefbc19c82616a68 upstream. _copy_from_pages() used to copy data from the temporary buffer to the user passed buffer is passed the wrong size parameter when copying data. res.acl_len contains both the bitmap and acl lenghts while acl_len contains the acl length after adjusting for the bitmap size. Signed-off-by: Sachin Prabhu <sprabhu@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Josh Boyer <jwboyer@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-13CIFS: Fix VFS lock usage for oplocked filesPavel Shilovsky
commit 66189be74ff5f9f3fd6444315b85be210d07cef2 upstream. We can deadlock if we have a write oplock and two processes use the same file handle. In this case the first process can't unlock its lock if the second process blocked on the lock in the same time. Fix it by using posix_lock_file rather than posix_lock_file_wait under cinode->lock_mutex. If we request a blocking lock and posix_lock_file indicates that there is another lock that prevents us, wait untill that lock is released and restart our call. Acked-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru> Signed-off-by: Steve French <sfrench@us.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02lockd: fix arg parsing for grace_period and timeout.NeilBrown
commit de5b8e8e047534aac6bc9803f96e7257436aef9c upstream. If you try to set grace_period or timeout via a module parameter to lockd, and do this on a big-endian machine where sizeof(int) != sizeof(unsigned long) it won't work. This number given will be effectively shifted right by the difference in those two sizes. So cast kp->arg properly to get correct result. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02NFSv4.1: Fix layoutcommit error handlingTrond Myklebust
commit e59d27e05a6435f8c04d5ad843f37fa795f2eaaa upstream. Firstly, task->tk_status will always return negative error values, so the current tests for 'NFS4ERR_DELEG_REVOKED' etc. are all being ignored. Secondly, clean up the code so that we only need to test task->tk_status once! Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02NFSv4: Fix two infinite loops in the mount codeTrond Myklebust
commit 05e9cfb408b24debb3a85fd98edbfd09dd148881 upstream. We can currently loop forever in nfs4_lookup_root() and in nfs41_proc_secinfo_no_name(), if the first iteration returns a NFS4ERR_DELAY or something else that causes exception.retry to get set. Reported-by: Weston Andros Adamson <dros@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02xfs: Fix oops on IO error during xlog_recover_process_iunlinks()Jan Kara
commit d97d32edcd732110758799ae60af725e5110b3dc upstream. When an IO error happens during inode deletion run from xlog_recover_process_iunlinks() filesystem gets shutdown. Thus any subsequent attempt to read buffers fails. Code in xlog_recover_process_iunlinks() does not count with the fact that read of a buffer which was read a while ago can really fail which results in the oops on agi = XFS_BUF_TO_AGI(agibp); Fix the problem by cleaning up the buffer handling in xlog_recover_process_iunlinks() as suggested by Dave Chinner. We release buffer lock but keep buffer reference to AG buffer. That is enough for buffer to stay pinned in memory and we don't have to call xfs_read_agi() all the time. Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02vfs: fix d_ancestor() case in d_materialize_uniqueMichel Lespinasse
commit b18dafc86bb879d2f38a1743985d7ceb283c2f4d upstream. In d_materialise_unique() there are 3 subcases to the 'aliased dentry' case; in two subcases the inode i_lock is properly released but this does not occur in the -ELOOP subcase. This seems to have been introduced by commit 1836750115f2 ("fix loop checks in d_materialise_unique()"). Signed-off-by: Michel Lespinasse <walken@google.com> [ Added a comment, and moved the unlock to where we generate the -ELOOP, which seems to be more natural. You probably can't actually trigger this without a buggy network file server - d_materialize_unique() is for finding aliases on non-local filesystems, and the d_ancestor() case is for a hardlinked directory loop. But we should be robust in the case of such buggy servers anyway. ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02ext4: check for zero length extentTheodore Ts'o
commit 31d4f3a2f3c73f279ff96a7135d7202ef6833f12 upstream. Explicitly test for an extent whose length is zero, and flag that as a corrupted extent. This avoids a kernel BUG_ON assertion failure. Tested: Without this patch, the file system image found in tests/f_ext_zero_len/image.gz in the latest e2fsprogs sources causes a kernel panic. With this patch, an ext4 file system error is noted instead, and the file system is marked as being corrupted. https://bugzilla.kernel.org/show_bug.cgi?id=42859 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02ext4: fix race between sync and completed io workJeff Moyer
commit 491caa43639abcffaa645fbab372a7ef4ce2975c upstream. The following command line will leave the aio-stress process unkillable on an ext4 file system (in my case, mounted on /mnt/test): aio-stress -t 20 -s 10 -O -S -o 2 -I 1000 /mnt/test/aiostress.3561.4 /mnt/test/aiostress.3561.4.20 /mnt/test/aiostress.3561.4.19 /mnt/test/aiostress.3561.4.18 /mnt/test/aiostress.3561.4.17 /mnt/test/aiostress.3561.4.16 /mnt/test/aiostress.3561.4.15 /mnt/test/aiostress.3561.4.14 /mnt/test/aiostress.3561.4.13 /mnt/test/aiostress.3561.4.12 /mnt/test/aiostress.3561.4.11 /mnt/test/aiostress.3561.4.10 /mnt/test/aiostress.3561.4.9 /mnt/test/aiostress.3561.4.8 /mnt/test/aiostress.3561.4.7 /mnt/test/aiostress.3561.4.6 /mnt/test/aiostress.3561.4.5 /mnt/test/aiostress.3561.4.4 /mnt/test/aiostress.3561.4.3 /mnt/test/aiostress.3561.4.2 This is using the aio-stress program from the xfstests test suite. That particular command line tells aio-stress to do random writes to 20 files from 20 threads (one thread per file). The files are NOT preallocated, so you will get writes to random offsets within the file, thus creating holes and extending i_size. It also opens the file with O_DIRECT and O_SYNC. On to the problem. When an I/O requires unwritten extent conversion, it is queued onto the completed_io_list for the ext4 inode. Two code paths will pull work items from this list. The first is the ext4_end_io_work routine, and the second is ext4_flush_completed_IO, which is called via the fsync path (and O_SYNC handling, as well). There are two issues I've found in these code paths. First, if the fsync path beats the work routine to a particular I/O, the work routine will free the io_end structure! It does not take into account the fact that the io_end may still be in use by the fsync path. I've fixed this issue by adding yet another IO_END flag, indicating that the io_end is being processed by the fsync path. The second problem is that the work routine will make an assignment to io->flag outside of the lock. I have witnessed this result in a hang at umount. Moving the flag setting inside the lock resolved that problem. The problem was introduced by commit b82e384c7b ("ext4: optimize locking for end_io extent conversion"), which first appeared in 3.2. As such, the fix should be backported to that release (probably along with the unwritten extent conversion race fix). Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02ext4: fix race between unwritten extent conversion and truncateJeff Moyer
commit 266991b13890049ee1a6bb95b9817f06339ee3d7 upstream. The following comment in ext4_end_io_dio caught my attention: /* XXX: probably should move into the real I/O completion handler */ inode_dio_done(inode); The truncate code takes i_mutex, then calls inode_dio_wait. Because the ext4 code path above will end up dropping the mutex before it is reacquired by the worker thread that does the extent conversion, it seems to me that the truncate can happen out of order. Jan Kara mentioned that this might result in error messages in the system logs, but that should be the extent of the "damage." The fix is pretty straight-forward: don't call inode_dio_done until the extent conversion is complete. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02ext4: ignore EXT4_INODE_JOURNAL_DATA flag with delallocLukas Czerner
commit 3d2b158262826e8b75bbbfb7b97010838dd92ac7 upstream. Ext4 does not support data journalling with delayed allocation enabled. We even do not allow to mount the file system with delayed allocation and data journalling enabled, however it can be set via FS_IOC_SETFLAGS so we can hit the inode with EXT4_INODE_JOURNAL_DATA set even on file system mounted with delayed allocation (default) and that's where problem arises. The easies way to reproduce this problem is with the following set of commands: mkfs.ext4 /dev/sdd mount /dev/sdd /mnt/test1 dd if=/dev/zero of=/mnt/test1/file bs=1M count=4 chattr +j /mnt/test1/file dd if=/dev/zero of=/mnt/test1/file bs=1M count=4 conv=notrunc chattr -j /mnt/test1/file Additionally it can be reproduced quite reliably with xfstests 272 and 269. In fact the above reproducer is a part of test 272. To fix this we should ignore the EXT4_INODE_JOURNAL_DATA inode flag if the file system is mounted with delayed allocation. This can be easily done by fixing ext4_should_*_data() functions do ignore data journal flag when delalloc is set (suggested by Ted). We also have to set the appropriate address space operations for the inode (again, ignoring data journal flag if delalloc enabled). Additionally this commit introduces ext4_inode_journal_mode() function because ext4_should_*_data() has already had a lot of common code and this change is putting it all into one function so it is easier to read. Successfully tested with xfstests in following configurations: delalloc + data=ordered delalloc + data=writeback data=journal nodelalloc + data=ordered nodelalloc + data=writeback nodelalloc + data=journal Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02jbd2: clear BH_Delay & BH_Unwritten in journal_unmap_bufferEric Sandeen
commit 15291164b22a357cb211b618adfef4fa82fc0de3 upstream. journal_unmap_buffer()'s zap_buffer: code clears a lot of buffer head state ala discard_buffer(), but does not touch _Delay or _Unwritten as discard_buffer() does. This can be problematic in some areas of the ext4 code which assume that if they have found a buffer marked unwritten or delay, then it's a live one. Perhaps those spots should check whether it is mapped as well, but if jbd2 is going to tear down a buffer, let's really tear it down completely. Without this I get some fsx failures on sub-page-block filesystems up until v3.2, at which point 4e96b2dbbf1d7e81f22047a50f862555a6cb87cb and 189e868fa8fdca702eb9db9d8afc46b5cb9144c9 make the failures go away, because buried within that large change is some more flag clearing. I still think it's worth doing in jbd2, since ->invalidatepage leads here directly, and it's the right place to clear away these flags. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02NFSv4: Rate limit the state manager warning messagesTrond Myklebust
commit 9a3ba432330e504ac61ff0043dbdaba7cea0e35a upstream. Prevent the state manager from filling up system logs when recovery fails on the server. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02sysctl: protect poll() in entries that may go awayLucas De Marchi
commit 4e474a00d7ff746ed177ddae14fa8b2d4bad7a00 upstream. Protect code accessing ctl_table by grabbing the header with grab_header() and after releasing with sysctl_head_finish(). This is needed if poll() is called in entries created by modules: currently only hostname and domainname support poll(), but this bug may be triggered when/if modules use it and if user called poll() in a file that doesn't support it. Dave Jones reported the following when using a syscall fuzzer while hibernating/resuming: RIP: 0010:[<ffffffff81233e3e>] [<ffffffff81233e3e>] proc_sys_poll+0x4e/0x90 RAX: 0000000000000145 RBX: ffff88020cab6940 RCX: 0000000000000000 RDX: ffffffff81233df0 RSI: 6b6b6b6b6b6b6b6b RDI: ffff88020cab6940 [ ... ] Code: 00 48 89 fb 48 89 f1 48 8b 40 30 4c 8b 60 e8 b8 45 01 00 00 49 83 7c 24 28 00 74 2e 49 8b 74 24 30 48 85 f6 74 24 48 85 c9 75 32 <8b> 16 b8 45 01 00 00 48 63 d2 49 39 d5 74 10 8b 06 48 98 48 89 If an entry goes away while we are polling() it, ctl_table may not exist anymore. Reported-by: Dave Jones <davej@redhat.com> Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02proc-ns: use d_set_d_op() API to set dentry ops in proc_ns_instantiate().Pravin B Shelar
commit 1b26c9b334044cff6d1d2698f2be41bc7d9a0864 upstream. The namespace cleanup path leaks a dentry which holds a reference count on a network namespace. Keeping that network namespace from being freed when the last user goes away. Leaving things like vlan devices in the leaked network namespace. If you use ip netns add for much real work this problem becomes apparent pretty quickly. It light testing the problem hides because frequently you simply don't notice the leak. Use d_set_d_op() so that DCACHE_OP_* flags are set correctly. This issue exists back to 3.0. Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Reported-by: Justin Pettit <jpettit@nicira.com> Signed-off-by: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: Jesse Gross <jesse@nicira.com> Cc: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02CIFS: Fix a spurious error in cifs_push_posix_locksPavel Shilovsky
commit ce85852b90a214cf577fc1b4f49d99fd7e98784a upstream. Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru> Reviewed-by: Jeff Layton <jlayton@redhat.com> Reported-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Steve French <sfrench@us.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02cifs: fix issue mounting of DFS ROOT when redirecting from one domain ↵Jeff Layton
controller to the next commit 1daaae8fa4afe3df78ca34e724ed7e8187e4eb32 upstream. This patch fixes an issue when cifs_mount receives a STATUS_BAD_NETWORK_NAME error during cifs_get_tcon but is able to continue after an DFS ROOT referral. In this case, the return code variable is not reset prior to trying to mount from the system referred to. Thus, is_path_accessible is not executed and the final DFS referral is not performed causing a mount error. Use case: In DNS, example.com resolves to the secondary AD server ad2.example.com Our primary domain controller is ad1.example.com and has a DFS redirection set up from \\ad1\share\Users to \\files\share\Users. Mounting \\example.com\share\Users fails. Regression introduced by commit 724d9f1. Reviewed-by: Pavel Shilovsky <piastry@etersoft.ru Signed-off-by: Thomas Hadig <thomas@intapp.com> Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02CIFS: Respect negotiated MaxMpxCountPavel Shilovsky
commit 10b9b98e41ba248a899f6175ce96ee91431b6194 upstream. Some servers sets this value less than 50 that was hardcoded and we lost the connection if when we exceed this limit. Fix this by respecting this value - not sending more than the server allows. Reviewed-by: Jeff Layton <jlayton@samba.org> Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru> Signed-off-by: Steve French <smfrench@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02xfs: fix inode lookup raceDave Chinner
commit f30d500f809eca67a21704347ab14bb35877b5ee upstream. When we get concurrent lookups of the same inode that is not in the per-AG inode cache, there is a race condition that triggers warnings in unlock_new_inode() indicating that we are initialising an inode that isn't in a the correct state for a new inode. When we do an inode lookup via a file handle or a bulkstat, we don't serialise lookups at a higher level through the dentry cache (i.e. pathless lookup), and so we can get concurrent lookups of the same inode. The race condition is between the insertion of the inode into the cache in the case of a cache miss and a concurrently lookup: Thread 1 Thread 2 xfs_iget() xfs_iget_cache_miss() xfs_iread() lock radix tree radix_tree_insert() rcu_read_lock radix_tree_lookup lock inode flags XFS_INEW not set igrab() unlock inode flags rcu_read_unlock use uninitialised inode ..... lock inode flags set XFS_INEW unlock inode flags unlock radix tree xfs_setup_inode() inode flags = I_NEW unlock_new_inode() WARNING as inode flags != I_NEW This can lead to inode corruption, inode list corruption, etc, and is generally a bad thing to occur. Fix this by setting XFS_INEW before inserting the inode into the radix tree. This will ensure any concurrent lookup will find the new inode with XFS_INEW set and that forces the lookup to wait until the XFS_INEW flag is removed before allowing the lookup to succeed. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ben Myers <bpm@sgi.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02NFSv4: Return the delegation if the server returns NFS4ERR_OPENMODETrond Myklebust
commit 3114ea7a24d3264c090556a2444fc6d2c06176d4 upstream. If a setattr() fails because of an NFS4ERR_OPENMODE error, it is probably due to us holding a read delegation. Ensure that the recovery routines return that delegation in this case. Reported-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02NFS: Properly handle the case where the delegation is revokedTrond Myklebust
commit a1d0b5eebc4fd6e0edb02688b35f17f67f42aea5 upstream. If we know that the delegation stateid is bad or revoked, we need to remove that delegation as soon as possible, and then mark all the stateids that relied on that delegation for recovery. We cannot use the delegation as part of the recovery process. Also note that NFSv4.1 uses a different error code (NFS4ERR_DELEG_REVOKED) to indicate that the delegation was revoked. Finally, ensure that setlk() and setattr() can both recover safely from a revoked delegation. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02hugetlbfs: avoid taking i_mutex from hugetlbfs_read()Aneesh Kumar K.V
commit a05b0855fd15504972dba2358e5faa172a1e50ba upstream. Taking i_mutex in hugetlbfs_read() can result in deadlock with mmap as explained below Thread A: read() on hugetlbfs hugetlbfs_read() called i_mutex grabbed hugetlbfs_read_actor() called __copy_to_user() called page fault is triggered Thread B, sharing address space with A: mmap() the same file ->mmap_sem is grabbed on task_B->mm->mmap_sem hugetlbfs_file_mmap() is called attempt to grab ->i_mutex and block waiting for A to give it up Thread A: pagefault handled blocked on attempt to grab task_A->mm->mmap_sem, which happens to be the same thing as task_B->mm->mmap_sem. Block waiting for B to give it up. AFAIU the i_mutex locking was added to hugetlbfs_read() as per http://lkml.indiana.edu/hypermail/linux/kernel/0707.2/3066.html to take care of the race between truncate and read. This patch fixes this by looking at page->mapping under lock_page() (find_lock_page()) to ensure that the inode didn't get truncated in the range during a parallel read. Ideally we can extend the patch to make sure we don't increase i_size in mmap. But that will break userspace, because applications will now have to use truncate(2) to increase i_size in hugetlbfs. Based on the original patch from Hillf Danton. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02mm: thp: fix pmd_bad() triggering in code paths holding mmap_sem read modeAndrea Arcangeli
commit 1a5a9906d4e8d1976b701f889d8f35d54b928f25 upstream. In some cases it may happen that pmd_none_or_clear_bad() is called with the mmap_sem hold in read mode. In those cases the huge page faults can allocate hugepmds under pmd_none_or_clear_bad() and that can trigger a false positive from pmd_bad() that will not like to see a pmd materializing as trans huge. It's not khugepaged causing the problem, khugepaged holds the mmap_sem in write mode (and all those sites must hold the mmap_sem in read mode to prevent pagetables to go away from under them, during code review it seems vm86 mode on 32bit kernels requires that too unless it's restricted to 1 thread per process or UP builds). The race is only with the huge pagefaults that can convert a pmd_none() into a pmd_trans_huge(). Effectively all these pmd_none_or_clear_bad() sites running with mmap_sem in read mode are somewhat speculative with the page faults, and the result is always undefined when they run simultaneously. This is probably why it wasn't common to run into this. For example if the madvise(MADV_DONTNEED) runs zap_page_range() shortly before the page fault, the hugepage will not be zapped, if the page fault runs first it will be zapped. Altering pmd_bad() not to error out if it finds hugepmds won't be enough to fix this, because zap_pmd_range would then proceed to call zap_pte_range (which would be incorrect if the pmd become a pmd_trans_huge()). The simplest way to fix this is to read the pmd in the local stack (regardless of what we read, no need of actual CPU barriers, only compiler barrier needed), and be sure it is not changing under the code that computes its value. Even if the real pmd is changing under the value we hold on the stack, we don't care. If we actually end up in zap_pte_range it means the pmd was not none already and it was not huge, and it can't become huge from under us (khugepaged locking explained above). All we need is to enforce that there is no way anymore that in a code path like below, pmd_trans_huge can be false, but pmd_none_or_clear_bad can run into a hugepmd. The overhead of a barrier() is just a compiler tweak and should not be measurable (I only added it for THP builds). I don't exclude different compiler versions may have prevented the race too by caching the value of *pmd on the stack (that hasn't been verified, but it wouldn't be impossible considering pmd_none_or_clear_bad, pmd_bad, pmd_trans_huge, pmd_none are all inlines and there's no external function called in between pmd_trans_huge and pmd_none_or_clear_bad). if (pmd_trans_huge(*pmd)) { if (next-addr != HPAGE_PMD_SIZE) { VM_BUG_ON(!rwsem_is_locked(&tlb->mm->mmap_sem)); split_huge_page_pmd(vma->vm_mm, pmd); } else if (zap_huge_pmd(tlb, vma, pmd, addr)) continue; /* fall through */ } if (pmd_none_or_clear_bad(pmd)) Because this race condition could be exercised without special privileges this was reported in CVE-2012-1179. The race was identified and fully explained by Ulrich who debugged it. I'm quoting his accurate explanation below, for reference. ====== start quote ======= mapcount 0 page_mapcount 1 kernel BUG at mm/huge_memory.c:1384! At some point prior to the panic, a "bad pmd ..." message similar to the following is logged on the console: mm/memory.c:145: bad pmd ffff8800376e1f98(80000000314000e7). The "bad pmd ..." message is logged by pmd_clear_bad() before it clears the page's PMD table entry. 143 void pmd_clear_bad(pmd_t *pmd) 144 { -> 145 pmd_ERROR(*pmd); 146 pmd_clear(pmd); 147 } After the PMD table entry has been cleared, there is an inconsistency between the actual number of PMD table entries that are mapping the page and the page's map count (_mapcount field in struct page). When the page is subsequently reclaimed, __split_huge_page() detects this inconsistency. 1381 if (mapcount != page_mapcount(page)) 1382 printk(KERN_ERR "mapcount %d page_mapcount %d\n", 1383 mapcount, page_mapcount(page)); -> 1384 BUG_ON(mapcount != page_mapcount(page)); The root cause of the problem is a race of two threads in a multithreaded process. Thread B incurs a page fault on a virtual address that has never been accessed (PMD entry is zero) while Thread A is executing an madvise() system call on a virtual address within the same 2 MB (huge page) range. virtual address space .---------------------. | | | | .-|---------------------| | | | | | |<-- B(fault) | | | 2 MB | |/////////////////////|-. huge < |/////////////////////| > A(range) page | |/////////////////////|-' | | | | | | '-|---------------------| | | | | '---------------------' - Thread A is executing an madvise(..., MADV_DONTNEED) system call on the virtual address range "A(range)" shown in the picture. sys_madvise // Acquire the semaphore in shared mode. down_read(&current->mm->mmap_sem) ... madvise_vma switch (behavior) case MADV_DONTNEED: madvise_dontneed zap_page_range unmap_vmas unmap_page_range zap_pud_range zap_pmd_range // // Assume that this huge page has never been accessed. // I.e. content of the PMD entry is zero (not mapped). // if (pmd_trans_huge(*pmd)) { // We don't get here due to the above assumption. } // // Assume that Thread B incurred a page fault and .---------> // sneaks in here as shown below. | // | if (pmd_none_or_clear_bad(pmd)) | { | if (unlikely(pmd_bad(*pmd))) | pmd_clear_bad | { | pmd_ERROR | // Log "bad pmd ..." message here. | pmd_clear | // Clear the page's PMD entry. | // Thread B incremented the map count | // in page_add_new_anon_rmap(), but | // now the page is no longer mapped | // by a PMD entry (-> inconsistency). | } | } | v - Thread B is handling a page fault on virtual address "B(fault)" shown in the picture. ... do_page_fault __do_page_fault // Acquire the semaphore in shared mode. down_read_trylock(&mm->mmap_sem) ... handle_mm_fault if (pmd_none(*pmd) && transparent_hugepage_enabled(vma)) // We get here due to the above assumption (PMD entry is zero). do_huge_pmd_anonymous_page alloc_hugepage_vma // Allocate a new transparent huge page here. ... __do_huge_pmd_anonymous_page ... spin_lock(&mm->page_table_lock) ... page_add_new_anon_rmap // Here we increment the page's map count (starts at -1). atomic_set(&page->_mapcount, 0) set_pmd_at // Here we set the page's PMD entry which will be cleared // when Thread A calls pmd_clear_bad(). ... spin_unlock(&mm->page_table_lock) The mmap_sem does not prevent the race because both threads are acquiring it in shared mode (down_read). Thread B holds the page_table_lock while the page's map count and PMD table entry are updated. However, Thread A does not synchronize on that lock. ====== end quote ======= [akpm@linux-foundation.org: checkpatch fixes] Reported-by: Ulrich Obergfell <uobergfe@redhat.com> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Jones <davej@redhat.com> Acked-by: Larry Woodman <lwoodman@redhat.com> Acked-by: Rik van Riel <riel@redhat.com> Cc: Mark Salter <msalter@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-02sysfs: Fix memory leak in sysfs_sd_setsecdata().Masami Ichikawa
commit 93518dd2ebafcc761a8637b2877008cfd748c202 upstream. This patch fixies follwing two memory leak patterns that reported by kmemleak. sysfs_sd_setsecdata() is called during sys_lsetxattr() operation. It checks sd->s_iattr is NULL or not. Then if it is NULL, it calls sysfs_init_inode_attrs() to allocate memory. That code is this. iattrs = sd->s_iattr; if (!iattrs) iattrs = sysfs_init_inode_attrs(sd); The iattrs recieves sysfs_init_inode_attrs()'s result, but sd->s_iattr doesn't know the address. so it needs to set correct address to sd->s_iattr to free memory in other function. unreferenced object 0xffff880250b73e60 (size 32): comm "systemd", pid 1, jiffies 4294683888 (age 94.553s) hex dump (first 32 bytes): 73 79 73 74 65 6d 5f 75 3a 6f 62 6a 65 63 74 5f system_u:object_ 72 3a 73 79 73 66 73 5f 74 3a 73 30 00 00 00 00 r:sysfs_t:s0.... backtrace: [<ffffffff814cb1d0>] kmemleak_alloc+0x73/0x98 [<ffffffff811270ab>] __kmalloc+0x100/0x12c [<ffffffff8120775a>] context_struct_to_string+0x106/0x210 [<ffffffff81207cc1>] security_sid_to_context_core+0x10b/0x129 [<ffffffff812090ef>] security_sid_to_context+0x10/0x12 [<ffffffff811fb0da>] selinux_inode_getsecurity+0x7d/0xa8 [<ffffffff811fb127>] selinux_inode_getsecctx+0x22/0x2e [<ffffffff811f4d62>] security_inode_getsecctx+0x16/0x18 [<ffffffff81191dad>] sysfs_setxattr+0x96/0x117 [<ffffffff811542f0>] __vfs_setxattr_noperm+0x73/0xd9 [<ffffffff811543d9>] vfs_setxattr+0x83/0xa1 [<ffffffff811544c6>] setxattr+0xcf/0x101 [<ffffffff81154745>] sys_lsetxattr+0x6a/0x8f [<ffffffff814efda9>] system_call_fastpath+0x16/0x1b [<ffffffffffffffff>] 0xffffffffffffffff unreferenced object 0xffff88024163c5a0 (size 96): comm "systemd", pid 1, jiffies 4294683888 (age 94.553s) hex dump (first 32 bytes): 00 00 00 00 ed 41 00 00 00 00 00 00 00 00 00 00 .....A.......... 00 00 00 00 00 00 00 00 0c 64 42 4f 00 00 00 00 .........dBO.... backtrace: [<ffffffff814cb1d0>] kmemleak_alloc+0x73/0x98 [<ffffffff81127402>] kmem_cache_alloc_trace+0xc4/0xee [<ffffffff81191cbe>] sysfs_init_inode_attrs+0x2a/0x83 [<ffffffff81191dd6>] sysfs_setxattr+0xbf/0x117 [<ffffffff811542f0>] __vfs_setxattr_noperm+0x73/0xd9 [<ffffffff811543d9>] vfs_setxattr+0x83/0xa1 [<ffffffff811544c6>] setxattr+0xcf/0x101 [<ffffffff81154745>] sys_lsetxattr+0x6a/0x8f [<ffffffff814efda9>] system_call_fastpath+0x16/0x1b [<ffffffffffffffff>] 0xffffffffffffffff ` Signed-off-by: Masami Ichikawa <masami256@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>