user/sven/linux.git, branch v3.2.87

Linux 3.2.87

2017-03-16T02:19:00Z

tty: n_hdlc: get rid of racy n_hdlc.tbuf

2017-03-16T02:18:59Z

commit 82f2341c94d270421f383641b7cd670e474db56b upstream. Currently N_HDLC line discipline uses a self-made singly linked list for data buffers and has n_hdlc.tbuf pointer for buffer retransmitting after an error. The commit be10eb7589337e5defbe214dae038a53dd21add8 ("tty: n_hdlc add buffer flushing") introduced racy access to n_hdlc.tbuf. After tx error concurrent flush_tx_queue() and n_hdlc_send_frames() can put one data buffer to tx_free_buf_list twice. That causes double free in n_hdlc_release(). Let's use standard kernel linked list and get rid of n_hdlc.tbuf: in case of tx error put current data buffer after the head of tx_buf_list. Signed-off-by: Alexander Popov Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings

list: introduce list_first_entry_or_null

2017-03-16T02:18:59Z

commit 6d7581e62f8be462440d7b22c6361f7c9fa4902b upstream. non-rcu variant of list_first_or_null_rcu Signed-off-by: Jiri Pirko Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings

TTY: n_hdlc, fix lockdep false positive

2017-03-16T02:18:59Z

commit e9b736d88af1a143530565929390cadf036dc799 upstream. The class of 4 n_hdls buf locks is the same because a single function n_hdlc_buf_list_init is used to init all the locks. But since flush_tx_queue takes n_hdlc->tx_buf_list.spinlock and then calls n_hdlc_buf_put which takes n_hdlc->tx_free_buf_list.spinlock, lockdep emits a warning: ============================================= [ INFO: possible recursive locking detected ] 4.3.0-25.g91e30a7-default #1 Not tainted --------------------------------------------- a.out/1248 is trying to acquire lock: (&(&list->spinlock)->rlock){......}, at: [] n_hdlc_buf_put+0x20/0x60 [n_hdlc] but task is already holding lock: (&(&list->spinlock)->rlock){......}, at: [] n_hdlc_tty_ioctl+0x127/0x1d0 [n_hdlc] other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(&list->spinlock)->rlock); lock(&(&list->spinlock)->rlock); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by a.out/1248: #0: (&tty->ldisc_sem){++++++}, at: [] tty_ldisc_ref_wait+0x20/0x50 #1: (&(&list->spinlock)->rlock){......}, at: [] n_hdlc_tty_ioctl+0x127/0x1d0 [n_hdlc] ... Call Trace: ... [] _raw_spin_lock_irqsave+0x50/0x70 [] n_hdlc_buf_put+0x20/0x60 [n_hdlc] [] n_hdlc_tty_ioctl+0x144/0x1d0 [n_hdlc] [] tty_ioctl+0x3f1/0xe40 ... Fix it by initializing the spin_locks separately. This removes also reduntand memset of a freshly kzallocated space. Signed-off-by: Jiri Slaby Reported-by: Dmitry Vyukov Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings

sctp: deny peeloff operation on asocs with threads sleeping on it

2017-03-16T02:18:58Z

commit dfcb9f4f99f1e9a49e43398a7bfbf56927544af1 upstream. commit 2dcab5984841 ("sctp: avoid BUG_ON on sctp_wait_for_sndbuf") attempted to avoid a BUG_ON call when the association being used for a sendmsg() is blocked waiting for more sndbuf and another thread did a peeloff operation on such asoc, moving it to another socket. As Ben Hutchings noticed, then in such case it would return without locking back the socket and would cause two unlocks in a row. Further analysis also revealed that it could allow a double free if the application managed to peeloff the asoc that is created during the sendmsg call, because then sctp_sendmsg() would try to free the asoc that was created only for that call. This patch takes another approach. It will deny the peeloff operation if there is a thread sleeping on the asoc, so this situation doesn't exist anymore. This avoids the issues described above and also honors the syscalls that are already being handled (it can be multiple sendmsg calls). Joint work with Xin Long. Fixes: 2dcab5984841 ("sctp: avoid BUG_ON on sctp_wait_for_sndbuf") Cc: Alexander Popov Cc: Ben Hutchings Signed-off-by: Marcelo Ricardo Leitner Signed-off-by: Xin Long Signed-off-by: David S. Miller [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings

sctp: avoid BUG_ON on sctp_wait_for_sndbuf

2017-03-16T02:18:58Z

commit 2dcab598484185dea7ec22219c76dcdd59e3cb90 upstream. Alexander Popov reported that an application may trigger a BUG_ON in sctp_wait_for_sndbuf if the socket tx buffer is full, a thread is waiting on it to queue more data and meanwhile another thread peels off the association being used by the first thread. This patch replaces the BUG_ON call with a proper error handling. It will return -EPIPE to the original sendmsg call, similarly to what would have been done if the association wasn't found in the first place. Acked-by: Alexander Popov Signed-off-by: Marcelo Ricardo Leitner Reviewed-by: Xin Long Signed-off-by: David S. Miller [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings

ipc/shm: Fix shmat mmap nil-page protection

2017-03-16T02:18:58Z

commit 95e91b831f87ac8e1f8ed50c14d709089b4e01b8 upstream. The issue is described here, with a nice testcase: https://bugzilla.kernel.org/show_bug.cgi?id=192931 The problem is that shmat() calls do_mmap_pgoff() with MAP_FIXED, and the address rounded down to 0. For the regular mmap case, the protection mentioned above is that the kernel gets to generate the address -- arch_get_unmapped_area() will always check for MAP_FIXED and return that address. So by the time we do security_mmap_addr(0) things get funky for shmat(). The testcase itself shows that while a regular user crashes, root will not have a problem attaching a nil-page. There are two possible fixes to this. The first, and which this patch does, is to simply allow root to crash as well -- this is also regular mmap behavior, ie when hacking up the testcase and adding mmap(... |MAP_FIXED). While this approach is the safer option, the second alternative is to ignore SHM_RND if the rounded address is 0, thus only having MAP_SHARED flags. This makes the behavior of shmat() identical to the mmap() case. The downside of this is obviously user visible, but does make sense in that it maintains semantics after the round-down wrt 0 address and mmap. Passes shm related ltp tests. Link: http://lkml.kernel.org/r/1486050195-18629-1-git-send-email-dave@stgolabs.net Signed-off-by: Davidlohr Bueso Reported-by: Gareth Evans Cc: Manfred Spraul Cc: Michael Kerrisk Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [bwh: Backported to 3.2: use SHMLBA constant instead of shmlba parameter] Signed-off-by: Ben Hutchings

Revert "KVM: x86: expose MSR_TSC_AUX to userspace"

2017-03-16T02:18:58Z

This reverts commit bc48f6f5a8c6d628a1af649306eaf906493bb986, which was commit 9dbe6cf941a6fe82933aef565e4095fb10f65023 upstream. It depends on several other large commits to work, and without them causes a regression. References: https://bugzilla.redhat.com/show_bug.cgi?id=1408333 Signed-off-by: Ben Hutchings Cc: Eric Wheeler

igmp, mld: Fix memory leak in igmpv3/mld_del_delrec()

2017-03-16T02:18:58Z

commit 9c8bb163ae784be4f79ae504e78c862806087c54 upstream. In function igmpv3/mld_add_delrec() we allocate pmc and put it in idev->mc_tomb, so we should free it when we don't need it in del_delrec(). But I removed kfree(pmc) incorrectly in latest two patches. Now fix it. Fixes: 24803f38a5c0 ("igmp: do not remove igmp souce list info when ...") Fixes: 1666d49e1d41 ("mld: do not remove mld souce list info when ...") Reported-by: Daniel Borkmann Signed-off-by: Hangbin Liu Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings

mld: do not remove mld souce list info when set link down

2017-03-16T02:18:58Z

commit 1666d49e1d416fcc2cce708242a52fe3317ea8ba upstream. This is an IPv6 version of commit 24803f38a5c0 ("igmp: do not remove igmp souce list..."). In mld_del_delrec(), we will restore back all source filter info instead of flush them. Move mld_clear_delrec() from ipv6_mc_down() to ipv6_mc_destroy_dev() since we should not remove source list info when set link down. Remove igmp6_group_dropped() in ipv6_mc_destroy_dev() since we have called it in ipv6_mc_down(). Also clear all source info after igmp6_group_dropped() instead of in it because ipv6_mc_down() will call igmp6_group_dropped(). Signed-off-by: Hangbin Liu Signed-off-by: David S. Miller [bwh: Backported to 3.2: - Timer code moved around in ipv6_mc_down() is different - Adjust context] Signed-off-by: Ben Hutchings