linux/kernel, branch v5.19

Merge tag 'x86_urgent_for_v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2022-07-31T16:26:53Z

Pull x86 fixes from Borislav Petkov: - Update the 'mitigations=' kernel param documentation - Check the IBPB feature flag before enabling IBPB in firmware calls because cloud vendors' fantasy when it comes to creating guest configurations is unlimited - Unexport sev_es_ghcb_hv_call() before 5.19 releases now that HyperV doesn't need it anymore - Remove dead CONFIG_* items * tag 'x86_urgent_for_v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: docs/kernel-parameters: Update descriptions for "mitigations=" param with retbleed x86/bugs: Do not enable IBPB at firmware entry when IBPB is not available Revert "x86/sev: Expose sev_es_ghcb_hv_call() for use by HyperV" x86/configs: Update configs in x86_debug.config

Merge tag 'locking_urgent_for_v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2022-07-31T16:21:13Z

Pull locking fix from Borislav Petkov: - Avoid rwsem lockups in certain situations when handling the handoff bit * tag 'locking_urgent_for_v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/rwsem: Allow slowpath writer to ignore handoff bit if not set by first waiter

locking/rwsem: Allow slowpath writer to ignore handoff bit if not set by first waiter

2022-07-30T08:58:28Z

With commit d257cc8cb8d5 ("locking/rwsem: Make handoff bit handling more consistent"), the writer that sets the handoff bit can be interrupted out without clearing the bit if the wait queue isn't empty. This disables reader and writer optimistic lock spinning and stealing. Now if a non-first writer in the queue is somehow woken up or a new waiter enters the slowpath, it can't acquire the lock. This is not the case before commit d257cc8cb8d5 as the writer that set the handoff bit will clear it when exiting out via the out_nolock path. This is less efficient as the busy rwsem stays in an unlock state for a longer time. In some cases, this new behavior may cause lockups as shown in [1] and [2]. This patch allows a non-first writer to ignore the handoff bit if it is not originally set or initiated by the first waiter. This patch is shown to be effective in fixing the lockup problem reported in [1]. [1] https://lore.kernel.org/lkml/20220617134325.GC30825@techsingularity.net/ [2] https://lore.kernel.org/lkml/3f02975c-1a9d-be20-32cf-f1d8e3dfafcc@oracle.com/ Fixes: d257cc8cb8d5 ("locking/rwsem: Make handoff bit handling more consistent") Signed-off-by: Waiman Long Signed-off-by: Peter Zijlstra (Intel) Acked-by: John Donnelly Tested-by: Mel Gorman Link: https://lore.kernel.org/r/20220622200419.778799-1-longman@redhat.com

Merge tag 'wq-for-5.19-rc8-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

2022-07-29T18:20:40Z

Pull workqueue fix from Tejun Heo: "Just one commit to suppress a spurious warning added during the 5.19 cycle" * tag 'wq-for-5.19-rc8-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: Avoid a false warning in unbind_workers()

workqueue: Avoid a false warning in unbind_workers()

2022-07-29T17:49:02Z

Doing set_cpus_allowed_ptr() with wq_unbound_cpumask can be possible fails and trigger the false warning. Use cpu_possible_mask instead when wq_unbound_cpumask has no active CPUs. It is very easy to trigger the warning: Set wq_unbound_cpumask to a small set of CPUs. Offline all the CPUs of wq_unbound_cpumask. Offline an extra CPU and trigger the warning. Fixes: 10a5a651e3af ("workqueue: Restrict kworker in the offline CPU pool running on housekeeping CPUs") Signed-off-by: Lai Jiangshan Signed-off-by: Tejun Heo

watch_queue: Fix missing locking in add_watch_to_object()

2022-07-28T17:06:49Z

If a watch is being added to a queue, it needs to guard against interference from addition of a new watch, manual removal of a watch and removal of a watch due to some other queue being destroyed. KEYCTL_WATCH_KEY guards against this for the same {key,queue} pair by holding the key->sem writelocked and by holding refs on both the key and the queue - but that doesn't prevent interaction from other {key,queue} pairs. While add_watch_to_object() does take the spinlock on the event queue, it doesn't take the lock on the source's watch list. The assumption was that the caller would prevent that (say by taking key->sem) - but that doesn't prevent interference from the destruction of another queue. Fix this by locking the watcher list in add_watch_to_object(). Fixes: c73be61cede5 ("pipe: Add general notification queue support") Reported-by: syzbot+03d7b43290037d1f87ca@syzkaller.appspotmail.com Signed-off-by: David Howells cc: keyrings@vger.kernel.org Signed-off-by: Linus Torvalds

watch_queue: Fix missing rcu annotation

2022-07-28T17:06:49Z

Since __post_watch_notification() walks wlist->watchers with only the RCU read lock held, we need to use RCU methods to add to the list (we already use RCU methods to remove from the list). Fix add_watch_to_object() to use hlist_add_head_rcu() instead of hlist_add_head() for that list. Fixes: c73be61cede5 ("pipe: Add general notification queue support") Signed-off-by: David Howells Signed-off-by: Linus Torvalds

x86/configs: Update configs in x86_debug.config

2022-07-27T16:09:11Z

Commit 4675ff05de2d ("kmemcheck: rip it out") removed kmemcheck and its corresponding build config KMEMCHECK. Commit 0f620cefd775 ("objtool: Rename "VMLINUX_VALIDATION" -> "NOINSTR_VALIDATION"") renamed the debug config option. Adjust x86_debug.config to those changes in debug configs. Signed-off-by: Lukas Bulwahn Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20220722121815.27535-1-lukas.bulwahn@gmail.com

Merge tag 'sched_urgent_for_v5.19_rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2022-07-24T16:50:53Z

Pull scheduler fix from Borislav Petkov: "A single fix to correct a wrong BUG_ON() condition for deboosted tasks" * tag 'sched_urgent_for_v5.19_rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/deadline: Fix BUG_ON condition for deboosted tasks

Merge tag 'rcu-urgent.2022.07.21a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

2022-07-22T17:01:20Z

Pull RCU fix from Paul McKenney: "This contains a pair of commits that fix 282d8998e997 ("srcu: Prevent expedited GPs and blocking readers from consuming CPU"), which was itself a fix to an SRCU expedited grace-period problem that could prevent kernel live patching (KLP) from completing. That SRCU fix for KLP introduced large (as in minutes) boot-time delays to embedded Linux kernels running on qemu/KVM. These delays were due to the emulation of certain MMIO operations controlling memory layout, which were emulated with one expedited grace period per access. Common configurations required thousands of boot-time MMIO accesses, and thus thousands of boot-time expedited SRCU grace periods. In these configurations, the occasional sleeps that allowed KLP to proceed caused excessive boot delays. These commits preserve enough sleeps to permit KLP to proceed, but few enough that the virtual embedded kernels still boot reasonably quickly. This represents a regression introduced in the v5.19 merge window, and the bug is causing significant inconvenience" * tag 'rcu-urgent.2022.07.21a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: srcu: Make expedited RCU grace periods block even less frequently srcu: Block less aggressively for expedited grace periods