diff options
| author | Niels Pressel <npressel@ethz.ch> | 2026-08-02 14:44:23 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@kernel.org> | 2026-08-10 09:37:54 +0200 |
| commit | ada54c2ba652348c590d1ace6a2f4ff77cbbf809 (patch) | |
| tree | a0d71d60af6cdce6607b8d434e1bbfc0b826c654 /include/linux | |
| parent | 075b74841bd0065a3bda3440873c747938e69b68 (diff) | |
rseq: Prevent hard lockup on granted time slice extension
__exit_to_user_mode_loop() invokes rseq_grant_timeslice_extension() with
interrupts enabled. If the extension is granted it invokes
hrtimer_rearm_deferred_tif() to ensure that a pending deferred hrtimer
rearm is handled before exiting to user space.
Though this invokes __hrtimer_rearm_deferred() which expects to be invoked
with interrupts disabled as it takes hrtimer_cpu_base::lock with
raw_spin_lock(). That's a livelock waiting to happen and caught by lockdep:
WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit, CPU#1: slice_test
WARNING: inconsistent lock state
inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
Prevent this by disabling interrupts around the invocation of
hrtimer_rearm_deferred_tif() in rseq_grant_timeslice_extension().
[ tglx: Massaged change log ]
Fixes: 15dd3a948855 ("hrtimer: Push reprogramming timers into the interrupt return path")
Signed-off-by: Niels Pressel <npressel@ethz.ch>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260802124423.51616-1-npressel@ethz.ch
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/rseq_entry.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/rseq_entry.h b/include/linux/rseq_entry.h index ed9da6e41a2a..31ce349ed42c 100644 --- a/include/linux/rseq_entry.h +++ b/include/linux/rseq_entry.h @@ -233,6 +233,7 @@ efault: static __always_inline bool rseq_grant_slice_extension(unsigned long ti_work, unsigned long mask) { if (unlikely(__rseq_grant_slice_extension(ti_work & mask))) { + guard(irq)(); hrtimer_rearm_deferred_tif(ti_work); return true; } |