- 17 Sep, 2014 40 commits
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Pavel Shilovsky authored
commit a07d3220 upstream. CIFS servers process nlink counts differently for files and directories. In cifs_rename() if we the request fails on the existing target, we try to remove it through cifs_unlink() but this is not what we want to do for directories. As the result the following sequence of commands mkdir {1,2}; mv -T 1 2; rmdir {1,2}; mkdir {1,2}; echo foo > 2/bar and XFS test generic/023 fail with -ENOENT error. That's why the second mkdir reuses the existing inode (target inode of the mv -T command) with S_DEAD flag. Fix this by checking whether the target is directory or not and calling cifs_rmdir() rather than cifs_unlink() for directories. Signed-off-by:
Pavel Shilovsky <pshilovsky@samba.org> Signed-off-by:
Steve French <smfrench@gmail.com> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Pavel Shilovsky authored
commit b46799a8 upstream. When we requests rename we also need to update attributes of both source and target parent directories. Not doing it causes generic/309 xfstest to fail on SMB2 mounts. Fix this by marking these directories for force revalidating. Signed-off-by:
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Steve French authored
commit 18f39e7b upstream. As Raphael Geissert pointed out, tcon_error_exit can dereference tcon and there is one path in which tcon can be null. Signed-off-by:
Raphael Geissert <geissert@debian.org> Signed-off-by:
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Pavel Shilovsky authored
commit 038bc961 upstream. If we get into read_into_pages() from cifs_readv_receive() and then loose a network, we issue cifs_reconnect that moves all mids to a private list and issue their callbacks. The callback of the async read request sets a mid to retry, frees it and wakes up a process that waits on the rdata completion. After the connection is established we return from read_into_pages() with a short read, use the mid that was freed before and try to read the remaining data from the a newly created socket. Both actions are not what we want to do. In reconnect cases (-EAGAIN) we should not mask off the error with a short read but should return the error code instead. Acked-by:
Jeff Layton <jlayton@samba.org> Signed-off-by:
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Pavel Shilovsky authored
commit 21496687 upstream. The existing mapping causes unlink() call to return error after delete operation. Changing the mapping to -EACCES makes the client process the call like CIFS protocol does - reset dos attributes with ATTR_READONLY flag masked off and retry the operation. Signed-off-by:
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Ilya Dryomov authored
commit c27a3e4d upstream. We hard code cephx auth ticket buffer size to 256 bytes. This isn't enough for any moderate setups and, in case tickets themselves are not encrypted, leads to buffer overflows (ceph_x_decrypt() errors out, but ceph_decode_copy() doesn't - it's just a memcpy() wrapper). Since the buffer is allocated dynamically anyway, allocated it a bit later, at the point where we know how much is going to be needed. Fixes: http://tracker.ceph.com/issues/8979Signed-off-by:
Ilya Dryomov <ilya.dryomov@inktank.com> Reviewed-by:
Sage Weil <sage@redhat.com> Signed-off-by:
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Ilya Dryomov authored
commit 597cda35 upstream. Add a helper for processing individual cephx auth tickets. Needed for the next commit, which deals with allocating ticket buffers. (Most of the diff here is whitespace - view with git diff -b). Signed-off-by:
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Sage Weil authored
commit 73c3d481 upstream. We preallocate a few of the message types we get back from the mon. If we get a larger message than we are expecting, fall back to trying to allocate a new one instead of blindly using the one we have. Signed-off-by:
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Ilya Dryomov authored
commit 5f740d7e upstream. Determining ->last_piece based on the value of ->page_offset + length is incorrect because length here is the length of the entire message. ->last_piece set to false even if page array data item length is <= PAGE_SIZE, which results in invalid length passed to ceph_tcp_{send,recv}page() and causes various asserts to fire. # cat pages-cursor-init.sh #!/bin/bash rbd create --size 10 --image-format 2 foo FOO_DEV=$(rbd map foo) dd if=/dev/urandom of=$FOO_DEV bs=1M &>/dev/null rbd snap create foo@snap rbd snap protect foo@snap rbd clone foo@snap bar # rbd_resize calls librbd rbd_resize(), size is in bytes ./rbd_resize bar $(((4 << 20) + 512)) rbd resize --size 10 bar BAR_DEV=$(rbd map bar) # trigger a 512-byte copyup -- 512-byte page array data item dd if=/dev/urandom of=$BAR_DEV bs=1M count=1 seek=5 The problem exists only in ceph_msg_data_pages_cursor_init(), ceph_msg_data_pages_advance() does the right thing. The size_t cast is unnecessary. Signed-off-by:
Alex Elder <elder@linaro.org> Signed-off-by:
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Chris Mason authored
commit 85e584da upstream. xfs is using truncate_pagecache_range to invalidate the page cache during DIO reads. This is different from the other filesystems who only invalidate pages during DIO writes. truncate_pagecache_range is meant to be used when we are freeing the underlying data structs from disk, so it will zero any partial ranges in the page. This means a DIO read can zero out part of the page cache page, and it is possible the page will stay in cache. buffered reads will find an up to date page with zeros instead of the data actually on disk. This patch fixes things by using invalidate_inode_pages2_range instead. It preserves the page cache invalidation, but won't zero any pages. [dchinner: catch error and warn if it fails. Comment.] Signed-off-by:
Chris Mason <clm@fb.com> Reviewed-by:
Dave Chinner <dchinner@redhat.com> Reviewed-by:
Brian Foster <bfoster@redhat.com> Reviewed-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
Dave Chinner <david@fromorbit.com> Signed-off-by:
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Dave Chinner authored
commit 834ffca6 upstream. Similar to direct IO reads, direct IO writes are using truncate_pagecache_range to invalidate the page cache. This is incorrect due to the sub-block zeroing in the page cache that truncate_pagecache_range() triggers. This patch fixes things by using invalidate_inode_pages2_range instead. It preserves the page cache invalidation, but won't zero any pages. Signed-off-by:
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Dave Chinner authored
commit 22e757a4 upstream. generic/263 is failing fsx at this point with a page spanning EOF that cannot be invalidated. The operations are: 1190 mapwrite 0x52c00 thru 0x5e569 (0xb96a bytes) 1191 mapread 0x5c000 thru 0x5d636 (0x1637 bytes) 1192 write 0x5b600 thru 0x771ff (0x1bc00 bytes) where 1190 extents EOF from 0x54000 to 0x5e569. When the direct IO write attempts to invalidate the cached page over this range, it fails with -EBUSY and so any attempt to do page invalidation fails. The real question is this: Why can't that page be invalidated after it has been written to disk and cleaned? Well, there's data on the first two buffers in the page (1k block size, 4k page), but the third buffer on the page (i.e. beyond EOF) is failing drop_buffers because it's bh->b_state == 0x3, which is BH_Uptodate | BH_Dirty. IOWs, there's dirty buffers beyond EOF. Say what? OK, set_buffer_dirty() is called on all buffers from __set_page_buffers_dirty(), regardless of whether the buffer is beyond EOF or not, which means that when we get to ->writepage, we have buffers marked dirty beyond EOF that we need to clean. So, we need to implement our own .set_page_dirty method that doesn't dirty buffers beyond EOF. This is messy because the buffer code is not meant to be shared and it has interesting locking issues on the buffer dirty bits. So just copy and paste it and then modify it to suit what we need. Note: the solutions the other filesystems and generic block code use of marking the buffers clean in ->writepage does not work for XFS. It still leaves dirty buffers beyond EOF and invalidations still fail. Hence rather than play whack-a-mole, this patch simply prevents those buffers from being dirtied in the first place. Signed-off-by:
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Dave Chinner authored
commit 5fd364fe upstream. When running xfs/305, I noticed that quotacheck was flushing dquot buffers that did not have the xfs_dquot_buf_ops verifiers attached: XFS (vdb): _xfs_buf_ioapply: no ops on block 0x1dc8/0x1dc8 ffff880052489000: 44 51 01 04 00 00 65 b8 00 00 00 00 00 00 00 00 DQ....e......... ffff880052489010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ ffff880052489020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ ffff880052489030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ CPU: 1 PID: 2376 Comm: mount Not tainted 3.16.0-rc2-dgc+ #306 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 ffff88006fe38000 ffff88004a0ffae8 ffffffff81cf1cca 0000000000000001 ffff88004a0ffb88 ffffffff814d50ca 000010004a0ffc70 0000000000000000 ffff88006be56dc4 0000000000000021 0000000000001dc8 ffff88007c773d80 Call Trace: [<ffffffff81cf1cca>] dump_stack+0x45/0x56 [<ffffffff814d50ca>] _xfs_buf_ioapply+0x3ca/0x3d0 [<ffffffff810db520>] ? wake_up_state+0x20/0x20 [<ffffffff814d51f5>] ? xfs_bdstrat_cb+0x55/0xb0 [<ffffffff814d513b>] xfs_buf_iorequest+0x6b/0xd0 [<ffffffff814d51f5>] xfs_bdstrat_cb+0x55/0xb0 [<ffffffff814d53ab>] __xfs_buf_delwri_submit+0x15b/0x220 [<ffffffff814d6040>] ? xfs_buf_delwri_submit+0x30/0x90 [<ffffffff814d6040>] xfs_buf_delwri_submit+0x30/0x90 [<ffffffff8150f89d>] xfs_qm_quotacheck+0x17d/0x3c0 [<ffffffff81510591>] xfs_qm_mount_quotas+0x151/0x1e0 [<ffffffff814ed01c>] xfs_mountfs+0x56c/0x7d0 [<ffffffff814f0f12>] xfs_fs_fill_super+0x2c2/0x340 [<ffffffff811c9fe4>] mount_bdev+0x194/0x1d0 [<ffffffff814f0c50>] ? xfs_finish_flags+0x170/0x170 [<ffffffff814ef0f5>] xfs_fs_mount+0x15/0x20 [<ffffffff811ca8c9>] mount_fs+0x39/0x1b0 [<ffffffff811e4d67>] vfs_kern_mount+0x67/0x120 [<ffffffff811e757e>] do_mount+0x23e/0xad0 [<ffffffff8117abde>] ? __get_free_pages+0xe/0x50 [<ffffffff811e71e6>] ? copy_mount_options+0x36/0x150 [<ffffffff811e8103>] SyS_mount+0x83/0xc0 [<ffffffff81cfd40b>] tracesys+0xdd/0xe2 This was caused by dquot buffer readahead not attaching a verifier structure to the buffer when readahead was issued, resulting in the followup read of the buffer finding a valid buffer and so not attaching new verifiers to the buffer as part of the read. Also, when a verifier failure occurs, we then read the buffer without verifiers. Attach the verifiers manually after this read so that if the buffer is then written it will be verified that the corruption has been repaired. Further, when flushing a dquot we don't ask for a verifier when reading in the dquot buffer the dquot belongs to. Most of the time this isn't an issue because the buffer is still cached, but when it is not cached it will result in writing the dquot buffer without having the verfier attached. Signed-off-by:
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Dave Chinner authored
commit 67dc288c upstream. Crash testing of CRC enabled filesystems has resulted in a number of reports of bad CRCs being detected after the filesystem was mounted. Errors such as the following were being seen: XFS (sdb3): Mounting V5 Filesystem XFS (sdb3): Starting recovery (logdev: internal) XFS (sdb3): Metadata CRC error detected at xfs_agf_read_verify+0x5a/0x100 [xfs], block 0x1 XFS (sdb3): Unmount and run xfs_repair XFS (sdb3): First 64 bytes of corrupted metadata buffer: ffff880136ffd600: 58 41 47 46 00 00 00 01 00 00 00 00 00 0f aa 40 XAGF...........@ ffff880136ffd610: 00 02 6d 53 00 02 77 f8 00 00 00 00 00 00 00 01 ..mS..w......... ffff880136ffd620: 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00 03 ................ ffff880136ffd630: 00 00 00 04 00 08 81 d0 00 08 81 a7 00 00 00 00 ................ XFS (sdb3): metadata I/O error: block 0x1 ("xfs_trans_read_buf_map") error 74 numblks 1 The errors were typically being seen in AGF, AGI and their related btree block buffers some time after log recovery had run. Often it wasn't until later subsequent mounts that the problem was discovered. The common symptom was a buffer with the correct contents, but a CRC and an LSN that matched an older version of the contents. Some debug added to _xfs_buf_ioapply() indicated that buffers were being written without verifiers attached to them from log recovery, and Jan Kara isolated the cause to log recovery readahead an dit's interactions with buffers that had a more recent LSN on disk than the transaction being recovered. In this case, the buffer did not get a verifier attached, and os when the second phase of log recovery ran and recovered EFIs and unlinked inodes, the buffers were modified and written without the verifier running. Hence they had up to date contents, but stale LSNs and CRCs. Fix it by attaching verifiers to buffers we skip due to future LSN values so they don't escape into the buffer cache without the correct verifier attached. This patch is based on analysis and a patch from Jan Kara. Reported-by:
Jan Kara <jack@suse.cz> Reported-by:
Fanael Linithien <fanael4@gmail.com> Reported-by:
Grozdan <neutrino8@gmail.com> Signed-off-by:
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Doug Ledford authored
commit db1044d4 upstream. added struct sockaddr_storage to rdma_user_cm.h without also adding an include for linux/socket.h to make sure it is defined. Systemtap needs the header files to build standalone and cannot rely on other files to pre-include other headers, so add linux/socket.h to the list of includes in this file. Fixes: ee7aed45 ("RDMA/ucma: Support querying for AF_IB addresses") Signed-off-by:
Doug Ledford <dledford@redhat.com> Signed-off-by:
Roland Dreier <roland@purestorage.com> Signed-off-by:
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Steve Wise authored
commit 2f0304d2 upstream. If the user creates a listening cm_id with backlog of 0 the IWCM ends up not allowing any connection requests at all. The correct behavior is for the IWCM to pick a default value if the user backlog parameter is zero. Lustre from version 1.8.8 onward uses a backlog of 0, which breaks iwarp support without this fix. Signed-off-by:
Steve Wise <swise@opengridcomputing.com> Signed-off-by:
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NeilBrown authored
commit b3968552 upstream. When a raid10 commences a resync/recovery/reshape it allocates some buffer space. When a resync/recovery completes the buffer space is freed. But not when the reshape completes. This can result in a small memory leak. There is a subtle side-effect of this bug. When a RAID10 is reshaped to a larger array (more devices), the reshape is immediately followed by a "resync" of the new space. This "resync" will use the buffer space which was allocated for "reshape". This can cause problems including a "BUG" in the SCSI layer. So this is suitable for -stable. Fixes: 3ea7daa5Signed-off-by:
NeilBrown <neilb@suse.de> Signed-off-by:
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NeilBrown authored
commit ce0b0a46 upstream. raid10 reshape clears unwanted bits from a bio->bi_flags using a method which, while clumsy, worked until 3.10 when BIO_OWNS_VEC was added. Since then it clears that bit but shouldn't. This results in a memory leak. So change to used the approved method of clearing unwanted bits. As this causes a memory leak which can consume all of memory the fix is suitable for -stable. Fixes: a38352e0 Reported-by: mdraid.pkoch@dfgh.net (Peter Koch) Signed-off-by:
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NeilBrown authored
commit 9c4bdf69 upstream. During recovery of a double-degraded RAID6 it is possible for some blocks not to be recovered properly, leading to corruption. If a write happens to one block in a stripe that would be written to a missing device, and at the same time that stripe is recovering data to the other missing device, then that recovered data may not be written. This patch skips, in the double-degraded case, an optimisation that is only safe for single-degraded arrays. Bug was introduced in 2.6.32 and fix is suitable for any kernel since then. In an older kernel with separate handle_stripe5() and handle_stripe6() functions the patch must change handle_stripe6(). Fixes: 6c0069c0 Cc: Yuri Tikhonov <yur@emcraft.com> Cc: Dan Williams <dan.j.williams@intel.com> Reported-by:
"Manibalan P" <pmanibalan@amiindia.co.in> Tested-by:
Dan Williams <dan.j.williams@intel.com> Signed-off-by:
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NeilBrown authored
commit a40687ff upstream. If a stripe in a raid6 array received a write to each data block while the array is degraded, and if any of these writes to a missing device are not page-aligned, then a live-lock happens. In this case the P and Q blocks need to be read so that the part of the missing block which is *not* being updated by the write can be constructed. Due to a logic error, these blocks are not loaded, so the update cannot proceed and the stripe is 'handled' repeatedly in an infinite loop. This bug is unlikely as most writes are page aligned. However as it can lead to a livelock it is suitable for -stable. It was introduced in 3.16. Fixed: 67f45548Signed-off-by:
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NeilBrown authored
commit 2446dba0 upstream. Currently we don't abort recovery on a write error if the write error to the recovering device was triggerd by normal IO (as opposed to recovery IO). This means that for one bitmap region, the recovery might write to the recovering device for a few sectors, then not bother for subsequent sectors (as it never writes to failed devices). In this case the bitmap bit will be cleared, but it really shouldn't. The result is that if the recovering device fails and is then re-added (after fixing whatever hardware problem triggerred the failure), the second recovery won't redo the region it was in the middle of, so some of the device will not be recovered properly. If we abort the recovery, the region being processes will be cancelled (bit not cleared) and the whole region will be retried. As the bug can result in data corruption the patch is suitable for -stable. For kernels prior to 3.11 there is a conflict in raid10.c which will require care. Original-from: jiao hui <jiaohui@bwstor.com.cn> Reported-and-tested-by:
jiao hui <jiaohui@bwstor.com.cn> Signed-off-by:
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Al Viro authored
commit 12a5b529 upstream. Since 3.14 we had copy_tree() get the shadowing wrong - if we had one vfsmount shadowing another (i.e. if A is a slave of B, C is mounted on A/foo, then D got mounted on B/foo creating D' on A/foo shadowed by C), copy_tree() of A would make a copy of D' shadow the the copy of C, not the other way around. It's easy to fix, fortunately - just make sure that mount follows the one that shadows it in mnt_child as well as in mnt_hash, and when copy_tree() decides to attach a new mount, check if the last child it has added to the same parent should be shadowing the new one. And if it should, just use the same logics commit_tree() has - put the new mount into the hash and children lists right after the one that should shadow it. Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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Ilya Dryomov authored
commit bc1ecc65 upstream. While it was never a good idea to sleep in request_fn(), commit 34c6bc2c ("locking/mutexes: Add extra reschedule point") made it a *bad* idea. mutex_lock() since 3.15 may reschedule *before* putting task on the mutex wait queue, which for tasks in !TASK_RUNNING state means block forever. request_fn() may be called with !TASK_RUNNING on the way to schedule() in io_schedule(). Offload request handling to a workqueue, one per rbd device, to avoid calling blocking primitives from rbd_request_fn(). Fixes: http://tracker.ceph.com/issues/8818Signed-off-by:
Eric Eastman <eric0e@aol.com> Tested-by:
Greg Wilson <greg.wilson@keepertech.com> Reviewed-by:
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Al Viro authored
commit 60bb4529 upstream. If DIO results in short write and sync write fails, we want to bugger off whether the DIO part has written anything or not; the logics on the return will take care of the right return value. Reported-by:
Anton Altaparmakov <aia21@cam.ac.uk> Signed-off-by:
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Vignesh Raman authored
commit 32333edb upstream. The commits 08c30aca "Bluetooth: Remove RFCOMM session refcnt" and 8ff52f7d "Bluetooth: Return RFCOMM session ptrs to avoid freed session" allow rfcomm_recv_ua and rfcomm_session_close to delete the session (and free the corresponding socket) and propagate NULL session pointer to the upper callers. Additional fix is required to terminate the loop in rfcomm_process_rx function to avoid use of freed 'sk' memory. The issue is only reproducible with kernel option CONFIG_PAGE_POISONING enabled making freed memory being changed and filled up with fixed char value used to unmask use-after-free issues. Signed-off-by:
Vignesh Raman <Vignesh_Raman@mentor.com> Signed-off-by:
Vitaly Kuzmichev <Vitaly_Kuzmichev@mentor.com> Acked-by:
Dean Jenkins <Dean_Jenkins@mentor.com> Signed-off-by:
Marcel Holtmann <marcel@holtmann.org> Signed-off-by:
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Johan Hedberg authored
commit 9f743d74 upstream. Commit 6c53823a reshuffled the way the authentication requirement gets set in the hci_io_capa_request_evt() function, but at the same time it failed to update an if-statement where cp.authentication is used before it has been initialized. The correct value the code should be looking for in this if-statement is conn->auth_type. Signed-off-by:
Johan Hedberg <johan.hedberg@intel.com> Signed-off-by:
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Vladimir Davydov authored
commit 093facf3 upstream. If the current process is exiting, lingering on socket close will make it unkillable, so we should avoid it. Reproducer: #include <sys/types.h> #include <sys/socket.h> #define BTPROTO_L2CAP 0 #define BTPROTO_SCO 2 #define BTPROTO_RFCOMM 3 int main() { int fd; struct linger ling; fd = socket(PF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM); //or: fd = socket(PF_BLUETOOTH, SOCK_DGRAM, BTPROTO_L2CAP); //or: fd = socket(PF_BLUETOOTH, SOCK_SEQPACKET, BTPROTO_SCO); ling.l_onoff = 1; ling.l_linger = 1000000000; setsockopt(fd, SOL_SOCKET, SO_LINGER, &ling, sizeof(ling)); return 0; } Signed-off-by:
Vladimir Davydov <vdavydov@parallels.com> Signed-off-by:
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Johan Hedberg authored
commit 6c53823a upstream. When we need to make the decision whether to perform just-works or real user confirmation we need to know the exact local authentication requirement that was passed to the controller. So far conn->auth_type (the local requirement) wasn't in one case updated appropriately in fear of the user confirmation being rejected later. The real problem however was not really that conn->auth_type couldn't represent the true value but that we were checking the local MITM requirement in an incorrect way. It's perfectly fine to let auth_type follow what we tell the controller since we're still tracking the target security level with conn->pending_sec_level. This patch updates the check for local MITM requirement in the hci_user_confirm_request_evt function to use the locally requested security level and ensures that auth_type always represents what we tell the controller. All other code in hci_user_confirm_request_evt still uses the auth_type instead of pending_sec_level for determining whether to do just-works or not, since that's the only value that's in sync with what the remote device knows. Signed-off-by:
Szymon Janc <szymon.janc@tieto.com> Signed-off-by:
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Marcel Holtmann authored
commit 42bd6a56 upstream. The advertising data and scan response data are merged in the wrong order. It should be advertsing data first and then scan response data and not the other way around. Signed-off-by:
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Chin-Ran Lo authored
commit 396e04f4 upstream. After BT_CMD_HOST_SLEEP_ENABLE command finishes, driver should wait until getting BT_EVENT_HOST_SLEEP_ENABLE event to complete suspend procedure. Without this patch the suspend handler would return success earlier. By the time when the BT_EVENT_HOST_SLEEP_ENABLE event comes in the controller driver could have already turned off the bus clock. This causes kernel crash or system reboot eventually. Signed-off-by:
Chin-Ran Lo <crlo@marvell.com> Signed-off-by:
Jeff CF Chen <jeffc@marvell.com> Signed-off-by:
Amitkumar Karwar <akarwar@marvell.com> Signed-off-by:
Bing Zhao <bzhao@marvell.com> Signed-off-by:
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Al Viro authored
commit 81b6b061 upstream. We need the parents of victims alive until namespace_unlock() gets to dput() of the (ex-)mountpoints. However, that screws up the "is it busy" checks in case when we have shrinkable mounts that need to be killed. Solution: go ahead and decrement refcounts of parents right in umount_tree(), increment them again just before dropping rwsem in namespace_unlock() (and let the loop in the end of namespace_unlock() finally drop those references for good, as we do now). Parents can't get freed until we drop rwsem - at least one reference is kept until then, both in case when parent is among the victims and when it is not. So they'll still be around when we get to namespace_unlock(). Signed-off-by:
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Al Viro authored
commit 88b368f2 upstream. The check in __propagate_umount() ("has somebody explicitly mounted something on that slave?") is done *before* taking the already doomed victims out of the child lists. Signed-off-by:
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Eric W. Biederman authored
commit db181ce0 upstream. Kenton Varda <kenton@sandstorm.io> discovered that by remounting a read-only bind mount read-only in a user namespace the MNT_LOCK_READONLY bit would be cleared, allowing an unprivileged user to the remount a read-only mount read-write. Upon review of the code in remount it was discovered that the code allowed nosuid, noexec, and nodev to be cleared. It was also discovered that the code was allowing the per mount atime flags to be changed. The first naive patch to fix these issues contained the flaw that using default atime settings when remounting a filesystem could be disallowed. To avoid this problems in the future add tests to ensure unprivileged remounts are succeeding and failing at the appropriate times. Acked-by:
Serge E. Hallyn <serge.hallyn@ubuntu.com> Signed-off-by:
"Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by:
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Eric W. Biederman authored
commit ffbc6f0e upstream. Since March 2009 the kernel has treated the state that if no MS_..ATIME flags are passed then the kernel defaults to relatime. Defaulting to relatime instead of the existing atime state during a remount is silly, and causes problems in practice for people who don't specify any MS_...ATIME flags and to get the default filesystem atime setting. Those users may encounter a permission error because the default atime setting does not work. A default that does not work and causes permission problems is ridiculous, so preserve the existing value to have a default atime setting that is always guaranteed to work. Using the default atime setting in this way is particularly interesting for applications built to run in restricted userspace environments without /proc mounted, as the existing atime mount options of a filesystem can not be read from /proc/mounts. In practice this fixes user space that uses the default atime setting on remount that are broken by the permission checks keeping less privileged users from changing more privileged users atime settings. Acked-by:
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Eric W. Biederman authored
commit 9566d674 upstream. While invesgiating the issue where in "mount --bind -oremount,ro ..." would result in later "mount --bind -oremount,rw" succeeding even if the mount started off locked I realized that there are several additional mount flags that should be locked and are not. In particular MNT_NOSUID, MNT_NODEV, MNT_NOEXEC, and the atime flags in addition to MNT_READONLY should all be locked. These flags are all per superblock, can all be changed with MS_BIND, and should not be changable if set by a more privileged user. The following additions to the current logic are added in this patch. - nosuid may not be clearable by a less privileged user. - nodev may not be clearable by a less privielged user. - noexec may not be clearable by a less privileged user. - atime flags may not be changeable by a less privileged user. The logic with atime is that always setting atime on access is a global policy and backup software and auditing software could break if atime bits are not updated (when they are configured to be updated), and serious performance degradation could result (DOS attack) if atime updates happen when they have been explicitly disabled. Therefore an unprivileged user should not be able to mess with the atime bits set by a more privileged user. The additional restrictions are implemented with the addition of MNT_LOCK_NOSUID, MNT_LOCK_NODEV, MNT_LOCK_NOEXEC, and MNT_LOCK_ATIME mnt flags. Taken together these changes and the fixes for MNT_LOCK_READONLY should make it safe for an unprivileged user to create a user namespace and to call "mount --bind -o remount,... ..." without the danger of mount flags being changed maliciously. Acked-by:
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Eric W. Biederman authored
commit 07b64558 upstream. There are no races as locked mount flags are guaranteed to never change. Moving the test into do_remount makes it more visible, and ensures all filesystem remounts pass the MNT_LOCK_READONLY permission check. This second case is not an issue today as filesystem remounts are guarded by capable(CAP_DAC_ADMIN) and thus will always fail in less privileged mount namespaces, but it could become an issue in the future. Acked-by:
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Eric W. Biederman authored
commit a6138db8 upstream. Kenton Varda <kenton@sandstorm.io> discovered that by remounting a read-only bind mount read-only in a user namespace the MNT_LOCK_READONLY bit would be cleared, allowing an unprivileged user to the remount a read-only mount read-write. Correct this by replacing the mask of mount flags to preserve with a mask of mount flags that may be changed, and preserve all others. This ensures that any future bugs with this mask and remount will fail in an easy to detect way where new mount flags simply won't change. Acked-by:
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Steven Rostedt (Red Hat) authored
commit 021de3d9 upstream. After writting a test to try to trigger the bug that caused the ring buffer iterator to become corrupted, I hit another bug: WARNING: CPU: 1 PID: 5281 at kernel/trace/ring_buffer.c:3766 rb_iter_peek+0x113/0x238() Modules linked in: ipt_MASQUERADE sunrpc [...] CPU: 1 PID: 5281 Comm: grep Tainted: G W 3.16.0-rc3-test+ #143 Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./To be filled by O.E.M., BIOS SDBLI944.86P 05/08/2007 0000000000000000 ffffffff81809a80 ffffffff81503fb0 0000000000000000 ffffffff81040ca1 ffff8800796d6010 ffffffff810c138d ffff8800796d6010 ffff880077438c80 ffff8800796d6010 ffff88007abbe600 0000000000000003 Call Trace: [<ffffffff81503fb0>] ? dump_stack+0x4a/0x75 [<ffffffff81040ca1>] ? warn_slowpath_common+0x7e/0x97 [<ffffffff810c138d>] ? rb_iter_peek+0x113/0x238 [<ffffffff810c138d>] ? rb_iter_peek+0x113/0x238 [<ffffffff810c14df>] ? ring_buffer_iter_peek+0x2d/0x5c [<ffffffff810c6f73>] ? tracing_iter_reset+0x6e/0x96 [<ffffffff810c74a3>] ? s_start+0xd7/0x17b [<ffffffff8112b13e>] ? kmem_cache_alloc_trace+0xda/0xea [<ffffffff8114cf94>] ? seq_read+0x148/0x361 [<ffffffff81132d98>] ? vfs_read+0x93/0xf1 [<ffffffff81132f1b>] ? SyS_read+0x60/0x8e [<ffffffff8150bf9f>] ? tracesys+0xdd/0xe2 Debugging this bug, which triggers when the rb_iter_peek() loops too many times (more than 2 times), I discovered there's a case that can cause that function to legitimately loop 3 times! rb_iter_peek() is different than rb_buffer_peek() as the rb_buffer_peek() only deals with the reader page (it's for consuming reads). The rb_iter_peek() is for traversing the buffer without consuming it, and as such, it can loop for one more reason. That is, if we hit the end of the reader page or any page, it will go to the next page and try again. That is, we have this: 1. iter->head > iter->head_page->page->commit (rb_inc_iter() which moves the iter to the next page) try again 2. event = rb_iter_head_event() event->type_len == RINGBUF_TYPE_TIME_EXTEND rb_advance_iter() try again 3. read the event. But we never get to 3, because the count is greater than 2 and we cause the WARNING and return NULL. Up the counter to 3. Fixes: 69d1b839 "ring-buffer: Bind time extend and data events together" Signed-off-by:
Steven Rostedt <rostedt@goodmis.org> Signed-off-by:
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Steven Rostedt (Red Hat) authored
commit 651e22f2 upstream. When performing a consuming read, the ring buffer swaps out a page from the ring buffer with a empty page and this page that was swapped out becomes the new reader page. The reader page is owned by the reader and since it was swapped out of the ring buffer, writers do not have access to it (there's an exception to that rule, but it's out of scope for this commit). When reading the "trace" file, it is a non consuming read, which means that the data in the ring buffer will not be modified. When the trace file is opened, a ring buffer iterator is allocated and writes to the ring buffer are disabled, such that the iterator will not have issues iterating over the data. Although the ring buffer disabled writes, it does not disable other reads, or even consuming reads. If a consuming read happens, then the iterator is reset and starts reading from the beginning again. My tests would sometimes trigger this bug on my i386 box: WARNING: CPU: 0 PID: 5175 at kernel/trace/trace.c:1527 __trace_find_cmdline+0x66/0xaa() Modules linked in: CPU: 0 PID: 5175 Comm: grep Not tainted 3.16.0-rc3-test+ #8 Hardware name: /DG965MQ, BIOS MQ96510J.86A.0372.2006.0605.1717 06/05/2006 00000000 00000000 f09c9e1c c18796b3 c1b5d74c f09c9e4c c103a0e3 c1b5154b f09c9e78 00001437 c1b5d74c 000005f7 c10bd85a c10bd85a c1cac57c f09c9eb0 ed0e0000 f09c9e64 c103a185 00000009 f09c9e5c c1b5154b f09c9e78 f09c9e80^M Call Trace: [<c18796b3>] dump_stack+0x4b/0x75 [<c103a0e3>] warn_slowpath_common+0x7e/0x95 [<c10bd85a>] ? __trace_find_cmdline+0x66/0xaa [<c10bd85a>] ? __trace_find_cmdline+0x66/0xaa [<c103a185>] warn_slowpath_fmt+0x33/0x35 [<c10bd85a>] __trace_find_cmdline+0x66/0xaa^M [<c10bed04>] trace_find_cmdline+0x40/0x64 [<c10c3c16>] trace_print_context+0x27/0xec [<c10c4360>] ? trace_seq_printf+0x37/0x5b [<c10c0b15>] print_trace_line+0x319/0x39b [<c10ba3fb>] ? ring_buffer_read+0x47/0x50 [<c10c13b1>] s_show+0x192/0x1ab [<c10bfd9a>] ? s_next+0x5a/0x7c [<c112e76e>] seq_read+0x267/0x34c [<c1115a25>] vfs_read+0x8c/0xef [<c112e507>] ? seq_lseek+0x154/0x154 [<c1115ba2>] SyS_read+0x54/0x7f [<c188488e>] syscall_call+0x7/0xb ---[ end trace 3f507febd6b4cc83 ]--- >>>> ##### CPU 1 buffer started #### Which was the __trace_find_cmdline() function complaining about the pid in the event record being negative. After adding more test cases, this would trigger more often. Strangely enough, it would never trigger on a single test, but instead would trigger only when running all the tests. I believe that was the case because it required one of the tests to be shutting down via delayed instances while a new test started up. After spending several days debugging this, I found that it was caused by the iterator becoming corrupted. Debugging further, I found out why the iterator became corrupted. It happened with the rb_iter_reset(). As consuming reads may not read the full reader page, and only part of it, there's a "read" field to know where the last read took place. The iterator, must also start at the read position. In the rb_iter_reset() code, if the reader page was disconnected from the ring buffer, the iterator would start at the head page within the ring buffer (where writes still happen). But the mistake there was that it still used the "read" field to start the iterator on the head page, where it should always start at zero because readers never read from within the ring buffer where writes occur. I originally wrote a patch to have it set the iter->head to 0 instead of iter->head_page->read, but then I questioned why it wasn't always setting the iter to point to the reader page, as the reader page is still valid. The list_empty(reader_page->list) just means that it was successful in swapping out. But the reader_page may still have data. There was a bug report a long time ago that was not reproducible that had something about trace_pipe (consuming read) not matching trace (iterator read). This may explain why that happened. Anyway, the correct answer to this bug is to always use the reader page an not reset the iterator to inside the writable ring buffer. Fixes: d769041f "ring_buffer: implement new locking" Signed-off-by:
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David Vrabel authored
commit c12784c3 upstream. When using the FIFO-based event channel ABI, if the control block or the local HEADs are not reset after resuming the guest may see stale HEAD values and will fail to traverse the FIFO correctly. This may prevent one or more VCPUs from receiving any events following a resume. Signed-off-by:
David Vrabel <david.vrabel@citrix.com> Reviewed-by:
Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by:
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