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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-10-24 22:33:30 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-10-24 22:33:30 +0300 |
| commit | f6602a97a11a3ddc077889fec2c026113c33c670 (patch) | |
| tree | 7c9eb57eac0ab29e150dbde0e6edde60a50f2d11 /kernel | |
| parent | 2a91e897c0e199f5d4cdc1a15f948133b15ec1f3 (diff) | |
| parent | 31d8aaa87fcef1be5932f3813ea369e21bd3b11d (diff) | |
| download | linux-f6602a97a11a3ddc077889fec2c026113c33c670.tar.xz | |
Merge tag 'rcu-urgent.2022.10.20a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu
Pull RCU fix from Paul McKenney:
"Fix a regression caused by commit bf95b2bc3e42 ("rcu: Switch polled
grace-period APIs to ->gp_seq_polled"), which could incorrectly leave
interrupts enabled after an early-boot call to synchronize_rcu().
Such synchronize_rcu() calls must acquire leaf rcu_node locks in order
to properly interact with polled grace periods, but the code did not
take into account the possibility of synchronize_rcu() being invoked
from the portion of the boot sequence during which interrupts are
disabled.
This commit therefore switches the lock acquisition and release from
irq to irqsave/irqrestore"
* tag 'rcu-urgent.2022.10.20a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
rcu: Keep synchronize_rcu() from enabling irqs in early boot
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/rcu/tree.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 6bb8e72bc815..93416afebd59 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1403,30 +1403,32 @@ static void rcu_poll_gp_seq_end(unsigned long *snap) // where caller does not hold the root rcu_node structure's lock. static void rcu_poll_gp_seq_start_unlocked(unsigned long *snap) { + unsigned long flags; struct rcu_node *rnp = rcu_get_root(); if (rcu_init_invoked()) { lockdep_assert_irqs_enabled(); - raw_spin_lock_irq_rcu_node(rnp); + raw_spin_lock_irqsave_rcu_node(rnp, flags); } rcu_poll_gp_seq_start(snap); if (rcu_init_invoked()) - raw_spin_unlock_irq_rcu_node(rnp); + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); } // Make the polled API aware of the end of a grace period, but where // caller does not hold the root rcu_node structure's lock. static void rcu_poll_gp_seq_end_unlocked(unsigned long *snap) { + unsigned long flags; struct rcu_node *rnp = rcu_get_root(); if (rcu_init_invoked()) { lockdep_assert_irqs_enabled(); - raw_spin_lock_irq_rcu_node(rnp); + raw_spin_lock_irqsave_rcu_node(rnp, flags); } rcu_poll_gp_seq_end(snap); if (rcu_init_invoked()) - raw_spin_unlock_irq_rcu_node(rnp); + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); } /* |