Pull ext4 updates from Ted Ts'o:
"Fix a number of bugs, most notably a potential stale data exposure
after a crash and a potential BUG_ON crash if a file has the data
journalling flag enabled while it has dirty delayed allocation blocks
that haven't been written yet. Also fix a potential crash in the new
project quota code and a maliciously corrupted file system.
In addition, fix some DAX-specific bugs, including when there is a
transient ENOSPC situation and races between writes via direct I/O and
an mmap'ed segment that could lead to lost I/O.
Finally the usual set of miscellaneous cleanups"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (23 commits)
ext4: pre-zero allocated blocks for DAX IO
ext4: refactor direct IO code
ext4: fix race in transient ENOSPC detection
ext4: handle transient ENOSPC properly for DAX
dax: call get_blocks() with create == 1 for write faults to unwritten extents
ext4: remove unmeetable inconsisteny check from ext4_find_extent()
jbd2: remove excess descriptions for handle_s
ext4: remove unnecessary bio get/put
ext4: silence UBSAN in ext4_mb_init()
ext4: address UBSAN warning in mb_find_order_for_block()
ext4: fix oops on corrupted filesystem
ext4: fix check of dqget() return value in ext4_ioctl_setproject()
ext4: clean up error handling when orphan list is corrupted
ext4: fix hang when processing corrupted orphaned inode list
ext4: remove trailing \n from ext4_warning/ext4_error calls
ext4: fix races between changing inode journal mode and ext4_writepages
ext4: handle unwritten or delalloc buffers before enabling data journaling
ext4: fix jbd2 handle extension in ext4_ext_truncate_extend_restart()
ext4: do not ask jbd2 to write data for delalloc buffers
jbd2: add support for avoiding data writes during transaction commits
...
Pull scheduler updates from Ingo Molnar:
- massive CPU hotplug rework (Thomas Gleixner)
- improve migration fairness (Peter Zijlstra)
- CPU load calculation updates/cleanups (Yuyang Du)
- cpufreq updates (Steve Muckle)
- nohz optimizations (Frederic Weisbecker)
- switch_mm() micro-optimization on x86 (Andy Lutomirski)
- ... lots of other enhancements, fixes and cleanups.
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (66 commits)
ARM: Hide finish_arch_post_lock_switch() from modules
sched/core: Provide a tsk_nr_cpus_allowed() helper
sched/core: Use tsk_cpus_allowed() instead of accessing ->cpus_allowed
sched/loadavg: Fix loadavg artifacts on fully idle and on fully loaded systems
sched/fair: Correct unit of load_above_capacity
sched/fair: Clean up scale confusion
sched/nohz: Fix affine unpinned timers mess
sched/fair: Fix fairness issue on migration
sched/core: Kill sched_class::task_waking to clean up the migration logic
sched/fair: Prepare to fix fairness problems on migration
sched/fair: Move record_wakee()
sched/core: Fix comment typo in wake_q_add()
sched/core: Remove unused variable
sched: Make hrtick_notifier an explicit call
sched/fair: Make ilb_notifier an explicit call
sched/hotplug: Make activate() the last hotplug step
sched/hotplug: Move migration CPU_DYING to sched_cpu_dying()
sched/migration: Move CPU_ONLINE into scheduler state
sched/migration: Move calc_load_migrate() into CPU_DYING
sched/migration: Move prepare transition to SCHED_STARTING state
...
Pull support for killable rwsems from Ingo Molnar:
"This, by Michal Hocko, implements down_write_killable().
The main usecase will be to update mm_sem usage sites to use this new
API, to allow the mm-reaper introduced in commit aac4536355 ("mm,
oom: introduce oom reaper") to tear down oom victim address spaces
asynchronously with minimum latencies and without deadlock worries"
[ The vfs will want it too as the inode lock is changed from a mutex to
a rwsem due to the parallel lookup and readdir updates ]
* 'locking-rwsem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/rwsem: Fix comment on register clobbering
locking/rwsem: Fix down_write_killable()
locking/rwsem, x86: Add frame annotation for call_rwsem_down_write_failed_killable()
locking/rwsem: Provide down_write_killable()
locking/rwsem, x86: Provide __down_write_killable()
locking/rwsem, s390: Provide __down_write_killable()
locking/rwsem, ia64: Provide __down_write_killable()
locking/rwsem, alpha: Provide __down_write_killable()
locking/rwsem: Introduce basis for down_write_killable()
locking/rwsem, sparc: Drop superfluous arch specific implementation
locking/rwsem, sh: Drop superfluous arch specific implementation
locking/rwsem, xtensa: Drop superfluous arch specific implementation
locking/rwsem: Drop explicit memory barriers
locking/rwsem: Get rid of __down_write_nested()
In ext4, there is a race condition between changing inode journal mode
and ext4_writepages(). While ext4_writepages() is executed on a
non-journalled mode inode, the inode's journal mode could be enabled
by ioctl() and then, some pages dirtied after switching the journal
mode will be still exposed to ext4_writepages() in non-journaled mode.
To resolve this problem, we use fs-wide per-cpu rw semaphore by Jan
Kara's suggestion because we don't want to waste ext4_inode_info's
space for this extra rare case.
Signed-off-by: Daeho Jeong <daeho.jeong@samsung.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
While playing with the qstat statistics (in <debugfs>/qlockstat/) I ran into
the following splat on a VM when opening pv_hash_hops:
divide error: 0000 [#1] SMP
...
RIP: 0010:[<ffffffff810b61fe>] [<ffffffff810b61fe>] qstat_read+0x12e/0x1e0
...
Call Trace:
[<ffffffff811cad7c>] ? mem_cgroup_commit_charge+0x6c/0xd0
[<ffffffff8119750c>] ? page_add_new_anon_rmap+0x8c/0xd0
[<ffffffff8118d3b9>] ? handle_mm_fault+0x1439/0x1b40
[<ffffffff811937a9>] ? do_mmap+0x449/0x550
[<ffffffff811d3de3>] ? __vfs_read+0x23/0xd0
[<ffffffff811d4ab2>] ? rw_verify_area+0x52/0xd0
[<ffffffff811d4bb1>] ? vfs_read+0x81/0x120
[<ffffffff811d5f12>] ? SyS_read+0x42/0xa0
[<ffffffff815720f6>] ? entry_SYSCALL_64_fastpath+0x1e/0xa8
Fix this by verifying that qstat_pv_kick_unlock is in fact non-zero,
similarly to what the qstat_pv_latency_wake case does, as if nothing
else, this can come from resetting the statistics, thus having 0 kicks
should be quite valid in this context.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Reviewed-by: Waiman Long <Waiman.Long@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Cc: waiman.long@hpe.com
Link: http://lkml.kernel.org/r/1460961103-24953-1-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
For the case of rtmutex torturing we will randomly call into the
boost() handler, including upon module exiting when the tasks are
deboosted before stopping. In such cases the task may or may not have
already been boosted, and therefore the NULL being explicitly passed
can occur anywhere. Currently we only assume that the task will is
at a higher prio, and in consequence, dereference a NULL pointer.
This patch fixes the case of a rmmod locktorture exploding while
pounding on the rtmutex lock (partial trace):
task: ffff88081026cf80 ti: ffff880816120000 task.ti: ffff880816120000
RSP: 0018:ffff880816123eb0 EFLAGS: 00010206
RAX: ffff88081026cf80 RBX: ffff880816bfa630 RCX: 0000000000160d1b
RDX: 0000000000000000 RSI: 0000000000000202 RDI: 0000000000000000
RBP: ffff88081026cf80 R08: 000000000000001f R09: ffff88017c20ca80
R10: 0000000000000000 R11: 000000000048c316 R12: ffffffffa05d1840
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88203f880000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000008 CR3: 0000000001c0a000 CR4: 00000000000406e0
Stack:
ffffffffa05d141d ffff880816bfa630 ffffffffa05d1922 ffff88081e70c2c0
ffff880816bfa630 ffffffff81095fed 0000000000000000 ffffffff8107bf60
ffff880816bfa630 ffffffff00000000 ffff880800000000 ffff880816123f08
Call Trace:
[<ffffffff81095fed>] kthread+0xbd/0xe0
[<ffffffff815cf40f>] ret_from_fork+0x3f/0x70
This patch ensures that if the random state pointer is not NULL and current
is not boosted, then do nothing.
RIP: 0010:[<ffffffffa05c6185>] [<ffffffffa05c6185>] torture_random+0x5/0x60 [torture]
[<ffffffffa05d141d>] torture_rtmutex_boost+0x1d/0x90 [locktorture]
[<ffffffffa05d1922>] lock_torture_writer+0xe2/0x170 [locktorture]
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bobby.prani@gmail.com
Cc: dhowells@redhat.com
Cc: dipankar@in.ibm.com
Cc: dvhart@linux.intel.com
Cc: edumazet@google.com
Cc: fweisbec@gmail.com
Cc: jiangshanlai@gmail.com
Cc: josh@joshtriplett.org
Cc: mathieu.desnoyers@efficios.com
Cc: oleg@redhat.com
Cc: rostedt@goodmis.org
Link: http://lkml.kernel.org/r/1460476038-27060-1-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
kcov provides code coverage collection for coverage-guided fuzzing
(randomized testing). Coverage-guided fuzzing is a testing technique
that uses coverage feedback to determine new interesting inputs to a
system. A notable user-space example is AFL
(http://lcamtuf.coredump.cx/afl/). However, this technique is not
widely used for kernel testing due to missing compiler and kernel
support.
kcov does not aim to collect as much coverage as possible. It aims to
collect more or less stable coverage that is function of syscall inputs.
To achieve this goal it does not collect coverage in soft/hard
interrupts and instrumentation of some inherently non-deterministic or
non-interesting parts of kernel is disbled (e.g. scheduler, locking).
Currently there is a single coverage collection mode (tracing), but the
API anticipates additional collection modes. Initially I also
implemented a second mode which exposes coverage in a fixed-size hash
table of counters (what Quentin used in his original patch). I've
dropped the second mode for simplicity.
This patch adds the necessary support on kernel side. The complimentary
compiler support was added in gcc revision 231296.
We've used this support to build syzkaller system call fuzzer, which has
found 90 kernel bugs in just 2 months:
https://github.com/google/syzkaller/wiki/Found-Bugs
We've also found 30+ bugs in our internal systems with syzkaller.
Another (yet unexplored) direction where kcov coverage would greatly
help is more traditional "blob mutation". For example, mounting a
random blob as a filesystem, or receiving a random blob over wire.
Why not gcov. Typical fuzzing loop looks as follows: (1) reset
coverage, (2) execute a bit of code, (3) collect coverage, repeat. A
typical coverage can be just a dozen of basic blocks (e.g. an invalid
input). In such context gcov becomes prohibitively expensive as
reset/collect coverage steps depend on total number of basic
blocks/edges in program (in case of kernel it is about 2M). Cost of
kcov depends only on number of executed basic blocks/edges. On top of
that, kernel requires per-thread coverage because there are always
background threads and unrelated processes that also produce coverage.
With inlined gcov instrumentation per-thread coverage is not possible.
kcov exposes kernel PCs and control flow to user-space which is
insecure. But debugfs should not be mapped as user accessible.
Based on a patch by Quentin Casasnovas.
[akpm@linux-foundation.org: make task_struct.kcov_mode have type `enum kcov_mode']
[akpm@linux-foundation.org: unbreak allmodconfig]
[akpm@linux-foundation.org: follow x86 Makefile layout standards]
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: syzkaller <syzkaller@googlegroups.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Tavis Ormandy <taviso@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Kees Cook <keescook@google.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: David Drysdale <drysdale@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
$ make tags
GEN tags
ctags: Warning: drivers/acpi/processor_idle.c:64: null expansion of name pattern "\1"
ctags: Warning: drivers/xen/events/events_2l.c:41: null expansion of name pattern "\1"
ctags: Warning: kernel/locking/lockdep.c:151: null expansion of name pattern "\1"
ctags: Warning: kernel/rcu/rcutorture.c:133: null expansion of name pattern "\1"
ctags: Warning: kernel/rcu/rcutorture.c:135: null expansion of name pattern "\1"
ctags: Warning: kernel/workqueue.c:323: null expansion of name pattern "\1"
ctags: Warning: net/ipv4/syncookies.c:53: null expansion of name pattern "\1"
ctags: Warning: net/ipv6/syncookies.c:44: null expansion of name pattern "\1"
ctags: Warning: net/rds/page.c:45: null expansion of name pattern "\1"
Which are all the result of the DEFINE_PER_CPU pattern:
scripts/tags.sh:200: '/\<DEFINE_PER_CPU([^,]*, *\([[:alnum:]_]*\)/\1/v/'
scripts/tags.sh:201: '/\<DEFINE_PER_CPU_SHARED_ALIGNED([^,]*, *\([[:alnum:]_]*\)/\1/v/'
The below cures them. All except the workqueue one are within reasonable
distance of the 80 char limit. TJ do you have any preference on how to
fix the wq one, or shall we just not care its too long?
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
