user/sven/linux.git/kernel, branch v3.2.75

sched/core: Clear the root_domain cpumasks in init_rootdomain()

2015-12-30T02:26:00Z

commit 8295c69925ad53ec32ca54ac9fc194ff21bc40e2 upstream. root_domain::rto_mask allocated through alloc_cpumask_var() contains garbage data, this may cause problems. For instance, When doing pull_rt_task(), it may do useless iterations if rto_mask retains some extra garbage bits. Worse still, this violates the isolated domain rule for clustered scheduling using cpuset, because the tasks(with all the cpus allowed) belongs to one root domain can be pulled away into another root domain. The patch cleans the garbage by using zalloc_cpumask_var() instead of alloc_cpumask_var() for root_domain::rto_mask allocation, thereby addressing the issues. Do the same thing for root_domain's other cpumask memembers: dlo_mask, span, and online. Signed-off-by: Xunlei Pang Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1449057179-29321-1-git-send-email-xlpang@redhat.com Signed-off-by: Ingo Molnar [bwh: Backported to 3.2: - There's no dlo_mask to initialise - Adjust filename] Signed-off-by: Ben Hutchings

sched/core: Remove false-positive warning from wake_up_process()

2015-12-30T02:26:00Z

commit 119d6f6a3be8b424b200dcee56e74484d5445f7e upstream. Because wakeups can (fundamentally) be late, a task might not be in the expected state. Therefore testing against a task's state is racy, and can yield false positives. Signed-off-by: Sasha Levin Signed-off-by: Peter Zijlstra (Intel) Acked-by: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: oleg@redhat.com Fixes: 9067ac85d533 ("wake_up_process() should be never used to wakeup a TASK_STOPPED/TRACED task") Link: http://lkml.kernel.org/r/1448933660-23082-1-git-send-email-sasha.levin@oracle.com Signed-off-by: Ingo Molnar [bwh: Backported to 3.2: adjust filename] Signed-off-by: Ben Hutchings

ring-buffer: Update read stamp with first real commit on page

2015-12-30T02:25:58Z

commit b81f472a208d3e2b4392faa6d17037a89442f4ce upstream. Do not update the read stamp after swapping out the reader page from the write buffer. If the reader page is swapped out of the buffer before an event is written to it, then the read_stamp may get an out of date timestamp, as the page timestamp is updated on the first commit to that page. rb_get_reader_page() only returns a page if it has an event on it, otherwise it will return NULL. At that point, check if the page being returned has events and has not been read yet. Then at that point update the read_stamp to match the time stamp of the reader page. Signed-off-by: Steven Rostedt Signed-off-by: Ben Hutchings

perf: Fix inherited events vs. tracepoint filters

2015-11-27T12:48:23Z

commit b71b437eedaed985062492565d9d421d975ae845 upstream. Arnaldo reported that tracepoint filters seem to misbehave (ie. not apply) on inherited events. The fix is obvious; filters are only set on the actual (parent) event, use the normal pattern of using this parent event for filters. This is safe because each child event has a reference to it. Reported-by: Arnaldo Carvalho de Melo Tested-by: Arnaldo Carvalho de Melo Signed-off-by: Peter Zijlstra (Intel) Cc: Adrian Hunter Cc: Arnaldo Carvalho de Melo Cc: David Ahern Cc: Frédéric Weisbecker Cc: Jiri Olsa Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Cc: Wang Nan Link: http://lkml.kernel.org/r/20151102095051.GN17308@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar Signed-off-by: Ben Hutchings

sched/core: Fix TASK_DEAD race in finish_task_switch()

2015-11-17T15:54:43Z

commit 95913d97914f44db2b81271c2e2ebd4d2ac2df83 upstream. So the problem this patch is trying to address is as follows: CPU0 CPU1 context_switch(A, B) ttwu(A) LOCK A->pi_lock A->on_cpu == 0 finish_task_switch(A) prev_state = A->state <-. WMB | A->on_cpu = 0; | UNLOCK rq0->lock | | context_switch(C, A) `-- A->state = TASK_DEAD prev_state == TASK_DEAD put_task_struct(A) context_switch(A, C) finish_task_switch(A) A->state == TASK_DEAD put_task_struct(A) The argument being that the WMB will allow the load of A->state on CPU0 to cross over and observe CPU1's store of A->state, which will then result in a double-drop and use-after-free. Now the comment states (and this was true once upon a long time ago) that we need to observe A->state while holding rq->lock because that will order us against the wakeup; however the wakeup will not in fact acquire (that) rq->lock; it takes A->pi_lock these days. We can obviously fix this by upgrading the WMB to an MB, but that is expensive, so we'd rather avoid that. The alternative this patch takes is: smp_store_release(&A->on_cpu, 0), which avoids the MB on some archs, but not important ones like ARM. Reported-by: Oleg Nesterov Signed-off-by: Peter Zijlstra (Intel) Acked-by: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Cc: manfred@colorfullife.com Cc: will.deacon@arm.com Fixes: e4a52bcb9a18 ("sched: Remove rq->lock from the first half of ttwu()") Link: http://lkml.kernel.org/r/20150929124509.GG3816@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar [bwh: Backported to 3.2: - Adjust filename - As smp_store_release() is not defined, use smp_mb()] Signed-off-by: Ben Hutchings

clocksource: Fix abs() usage w/ 64bit values

2015-11-17T15:54:41Z

commit 67dfae0cd72fec5cd158b6e5fb1647b7dbe0834c upstream. This patch fixes one cases where abs() was being used with 64-bit nanosecond values, where the result may be capped at 32-bits. This potentially could cause watchdog false negatives on 32-bit systems, so this patch addresses the issue by using abs64(). Signed-off-by: John Stultz Cc: Prarit Bhargava Cc: Richard Cochran Cc: Ingo Molnar Link: http://lkml.kernel.org/r/1442279124-7309-2-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings

genirq: Fix race in register_irq_proc()

2015-11-17T15:54:41Z

commit 95c2b17534654829db428f11bcf4297c059a2a7e upstream. Per-IRQ directories in procfs are created only when a handler is first added to the irqdesc, not when the irqdesc is created. In the case of a shared IRQ, multiple tasks can race to create a directory. This race condition seems to have been present forever, but is easier to hit with async probing. Signed-off-by: Ben Hutchings Link: http://lkml.kernel.org/r/1443266636.2004.2.camel@decadent.org.uk Signed-off-by: Thomas Gleixner

module: Fix locking in symbol_put_addr()

2015-11-17T15:54:40Z

commit 275d7d44d802ef271a42dc87ac091a495ba72fc5 upstream. Poma (on the way to another bug) reported an assertion triggering: [] module_assert_mutex_or_preempt+0x49/0x90 [] __module_address+0x32/0x150 [] __module_text_address+0x16/0x70 [] symbol_put_addr+0x29/0x40 [] dvb_frontend_detach+0x7d/0x90 [dvb_core] Laura Abbott produced a patch which lead us to inspect symbol_put_addr(). This function has a comment claiming it doesn't need to disable preemption around the module lookup because it holds a reference to the module it wants to find, which therefore cannot go away. This is wrong (and a false optimization too, preempt_disable() is really rather cheap, and I doubt any of this is on uber critical paths, otherwise it would've retained a pointer to the actual module anyway and avoided the second lookup). While its true that the module cannot go away while we hold a reference on it, the data structure we do the lookup in very much _CAN_ change while we do the lookup. Therefore fix the comment and add the required preempt_disable(). Reported-by: poma Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Rusty Russell Fixes: a6e6abd575fc ("module: remove module_text_address()") Signed-off-by: Ben Hutchings

fs: create and use seq_show_option for escaping

2015-10-13T02:46:08Z

commit a068acf2ee77693e0bf39d6e07139ba704f461c3 upstream. Many file systems that implement the show_options hook fail to correctly escape their output which could lead to unescaped characters (e.g. new lines) leaking into /proc/mounts and /proc/[pid]/mountinfo files. This could lead to confusion, spoofed entries (resulting in things like systemd issuing false d-bus "mount" notifications), and who knows what else. This looks like it would only be the root user stepping on themselves, but it's possible weird things could happen in containers or in other situations with delegated mount privileges. Here's an example using overlay with setuid fusermount trusting the contents of /proc/mounts (via the /etc/mtab symlink). Imagine the use of "sudo" is something more sneaky: $ BASE="ovl" $ MNT="$BASE/mnt" $ LOW="$BASE/lower" $ UP="$BASE/upper" $ WORK="$BASE/work/ 0 0 none /proc fuse.pwn user_id=1000" $ mkdir -p "$LOW" "$UP" "$WORK" $ sudo mount -t overlay -o "lowerdir=$LOW,upperdir=$UP,workdir=$WORK" none /mnt $ cat /proc/mounts none /root/ovl/mnt overlay rw,relatime,lowerdir=ovl/lower,upperdir=ovl/upper,workdir=ovl/work/ 0 0 none /proc fuse.pwn user_id=1000 0 0 $ fusermount -u /proc $ cat /proc/mounts cat: /proc/mounts: No such file or directory This fixes the problem by adding new seq_show_option and seq_show_option_n helpers, and updating the vulnerable show_option handlers to use them as needed. Some, like SELinux, need to be open coded due to unusual existing escape mechanisms. [akpm@linux-foundation.org: add lost chunk, per Kees] [keescook@chromium.org: seq_show_option should be using const parameters] Signed-off-by: Kees Cook Acked-by: Serge Hallyn Acked-by: Jan Kara Acked-by: Paul Moore Cc: J. R. Okajima Signed-off-by: Kees Cook Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [bwh: Backported to 3.2: - Drop changes to overlayfs, reiserfs - Drop vers option from cifs - ceph changes are all in one file - Adjust context] Signed-off-by: Ben Hutchings

perf: Fix fasync handling on inherited events

2015-10-13T02:46:02Z

commit fed66e2cdd4f127a43fd11b8d92a99bdd429528c upstream. Vince reported that the fasync signal stuff doesn't work proper for inherited events. So fix that. Installing fasync allocates memory and sets filp->f_flags |= FASYNC, which upon the demise of the file descriptor ensures the allocation is freed and state is updated. Now for perf, we can have the events stick around for a while after the original FD is dead because of references from child events. So we cannot copy the fasync pointer around. We can however consistently use the parent's fasync, as that will be updated. Reported-and-Tested-by: Vince Weaver Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho deMelo Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: eranian@google.com Link: http://lkml.kernel.org/r/1434011521.1495.71.camel@twins Signed-off-by: Ingo Molnar Signed-off-by: Ben Hutchings