diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2023-12-30 11:37:35 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-12-30 11:37:35 -0800 |
commit | 453f5db0619e2ad64076aab16ff5a00e0f7c53a2 (patch) | |
tree | ec9a0b998df99d14953c058d22714f1e5b2e3b4b /kernel/trace/ring_buffer.c | |
parent | b106bcf0f99ae0459f3c8c2f0af575ef9f5d9bde (diff) | |
parent | d05cb470663a2a1879277e544f69e660208f08f2 (diff) |
Merge tag 'trace-v6.7-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:
- Fix readers that are blocked on the ring buffer when buffer_percent
is 100%. They are supposed to wake up when the buffer is full, but
because the sub-buffer that the writer is on is never considered
"dirty" in the calculation, dirty pages will never equal nr_pages.
Add +1 to the dirty count in order to count for the sub-buffer that
the writer is on.
- When a reader is blocked on the "snapshot_raw" file, it is to be
woken up when a snapshot is done and be able to read the snapshot
buffer. But because the snapshot swaps the buffers (the main one with
the snapshot one), and the snapshot reader is waiting on the old
snapshot buffer, it was not woken up (because it is now on the main
buffer after the swap). Worse yet, when it reads the buffer after a
snapshot, it's not reading the snapshot buffer, it's reading the live
active main buffer.
Fix this by forcing a wakeup of all readers on the snapshot buffer
when a new snapshot happens, and then update the buffer that the
reader is reading to be back on the snapshot buffer.
- Fix the modification of the direct_function hash. There was a race
when new functions were added to the direct_function hash as when it
moved function entries from the old hash to the new one, a direct
function trace could be hit and not see its entry.
This is fixed by allocating the new hash, copy all the old entries
onto it as well as the new entries, and then use rcu_assign_pointer()
to update the new direct_function hash with it.
This also fixes a memory leak in that code.
- Fix eventfs ownership
* tag 'trace-v6.7-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
ftrace: Fix modification of direct_function hash while in use
tracing: Fix blocked reader of snapshot buffer
ring-buffer: Fix wake ups when buffer_percent is set to 100
eventfs: Fix file and directory uid and gid ownership
Diffstat (limited to 'kernel/trace/ring_buffer.c')
-rw-r--r-- | kernel/trace/ring_buffer.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 83eab547f1d1..9286f88fcd32 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -881,9 +881,14 @@ static __always_inline bool full_hit(struct trace_buffer *buffer, int cpu, int f if (!nr_pages || !full) return true; - dirty = ring_buffer_nr_dirty_pages(buffer, cpu); + /* + * Add one as dirty will never equal nr_pages, as the sub-buffer + * that the writer is on is not counted as dirty. + * This is needed if "buffer_percent" is set to 100. + */ + dirty = ring_buffer_nr_dirty_pages(buffer, cpu) + 1; - return (dirty * 100) > (full * nr_pages); + return (dirty * 100) >= (full * nr_pages); } /* @@ -944,7 +949,8 @@ void ring_buffer_wake_waiters(struct trace_buffer *buffer, int cpu) /* make sure the waiters see the new index */ smp_wmb(); - rb_wake_up_waiters(&rbwork->work); + /* This can be called in any context */ + irq_work_queue(&rbwork->work); } /** |