No need to duplicate them in both callers; make it return
ERR_PTR(-ENOMEM) on allocation failure instead of NULL and
it'll be able to report rpc_lookup_cred() failures just
fine. Callers are much happier that way...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Commit 1e39f384bb ("evm: fix build problems") makes the stub version
of security_old_inode_init_security() return 0 when CONFIG_SECURITY is
not set.
But that makes callers such as reiserfs_security_init() assume that
security_old_inode_init_security() has set name, value, and len
arguments properly - but security_old_inode_init_security() left them
uninitialized which then results in interesting failures.
Revert security_old_inode_init_security() to the old behavior of
returning EOPNOTSUPP since both callers (reiserfs and ocfs2) handle this
just fine.
[ Also fixed the S_PRIVATE(inode) case of the actual non-stub
security_old_inode_init_security() function to return EOPNOTSUPP
for the same reason, as pointed out by Mimi Zohar.
It got incorrectly changed to match the new function in commit
fb88c2b6cb: "evm: fix security/security_old_init_security return
code". - Linus ]
Reported-by: Jorge Bastos <mysql.jorge@decimal.pt>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Unlike all of the other cpuid bits, the TSC deadline timer bit is set
unconditionally, regardless of what userspace wants.
This is broken in several ways:
- if userspace doesn't use KVM_CREATE_IRQCHIP, and doesn't emulate the TSC
deadline timer feature, a guest that uses the feature will break
- live migration to older host kernels that don't support the TSC deadline
timer will cause the feature to be pulled from under the guest's feet;
breaking it
- guests that are broken wrt the feature will fail.
Fix by not enabling the feature automatically; instead report it to userspace.
Because the feature depends on KVM_CREATE_IRQCHIP, which we cannot guarantee
will be called, we expose it via a KVM_CAP_TSC_DEADLINE_TIMER and not
KVM_GET_SUPPORTED_CPUID.
Fixes the Illumos guest kernel, which uses the TSC deadline timer feature.
[avi: add the KVM_CAP + documentation]
Reported-by: Alexey Zaytsev <alexey.zaytsev@gmail.com>
Tested-by: Alexey Zaytsev <alexey.zaytsev@gmail.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Currently, the *_global_[un]lock_online() routines are not at all synchronized
with CPU hotplug. Soft-lockups detected as a consequence of this race was
reported earlier at https://lkml.org/lkml/2011/8/24/185. (Thanks to Cong Meng
for finding out that the root-cause of this issue is the race condition
between br_write_[un]lock() and CPU hotplug, which results in the lock states
getting messed up).
Fixing this race by just adding {get,put}_online_cpus() at appropriate places
in *_global_[un]lock_online() is not a good option, because, then suddenly
br_write_[un]lock() would become blocking, whereas they have been kept as
non-blocking all this time, and we would want to keep them that way.
So, overall, we want to ensure 3 things:
1. br_write_lock() and br_write_unlock() must remain as non-blocking.
2. The corresponding lock and unlock of the per-cpu spinlocks must not happen
for different sets of CPUs.
3. Either prevent any new CPU online operation in between this lock-unlock, or
ensure that the newly onlined CPU does not proceed with its corresponding
per-cpu spinlock unlocked.
To achieve all this:
(a) We introduce a new spinlock that is taken by the *_global_lock_online()
routine and released by the *_global_unlock_online() routine.
(b) We register a callback for CPU hotplug notifications, and this callback
takes the same spinlock as above.
(c) We maintain a bitmap which is close to the cpu_online_mask, and once it is
initialized in the lock_init() code, all future updates to it are done in
the callback, under the above spinlock.
(d) The above bitmap is used (instead of cpu_online_mask) while locking and
unlocking the per-cpu locks.
The callback takes the spinlock upon the CPU_UP_PREPARE event. So, if the
br_write_lock-unlock sequence is in progress, the callback keeps spinning,
thus preventing the CPU online operation till the lock-unlock sequence is
complete. This takes care of requirement (3).
The bitmap that we maintain remains unmodified throughout the lock-unlock
sequence, since all updates to it are managed by the callback, which takes
the same spinlock as the one taken by the lock code and released only by the
unlock routine. Combining this with (d) above, satisfies requirement (2).
Overall, since we use a spinlock (mentioned in (a)) to prevent CPU hotplug
operations from racing with br_write_lock-unlock, requirement (1) is also
taken care of.
By the way, it is to be noted that a CPU offline operation can actually run
in parallel with our lock-unlock sequence, because our callback doesn't react
to notifications earlier than CPU_DEAD (in order to maintain our bitmap
properly). And this means, since we use our own bitmap (which is stale, on
purpose) during the lock-unlock sequence, we could end up unlocking the
per-cpu lock of an offline CPU (because we had locked it earlier, when the
CPU was online), in order to satisfy requirement (2). But this is harmless,
though it looks a bit awkward.
Debugged-by: Cong Meng <mc@linux.vnet.ibm.com>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@vger.kernel.org
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
time/clocksource: Fix kernel-doc warnings
rtc: m41t80: Workaround broken alarm functionality
rtc: Expire alarms after the time is set.
Al Viro
Jan Kara
Jan Kiszka
Srivatsa S. Bhat
Linus Torvalds