The patch titled
Subject: aio: fix kioctx not being freed after cancellation at exit time
has been added to the -mm tree. Its filename is
aio-fix-kioctx-not-being-freed-after-cancellation-at-exit-time.patch
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------------------------------------------------------
From: Kent Overstreet <koverstreet@xxxxxxxxxx>
Subject: aio: fix kioctx not being freed after cancellation at exit time
The recent changes overhauling fs/aio.c introduced a bug that results in the
kioctx not being freed when outstanding kiocbs are cancelled at exit_aio()
time. Specifically, a kiocb that is cancelled has its completion events
discarded by batch_complete_aio(), which then fails to wake up the process
stuck in free_ioctx(). Fix this by removing the event suppression in
batch_complete_aio() and modify the wait_event() condition in free_ioctx()
appropriately.
This patch was tested with the cancel operation in the thread based code
posted yesterday.
Signed-off-by: Benjamin LaHaise <bcrl@xxxxxxxxx>
Signed-off-by: Kent Overstreet <koverstreet@xxxxxxxxxx>
Cc: Kent Overstreet <koverstreet@xxxxxxxxxx>
Cc: Josh Boyer <jwboyer@xxxxxxxxxx>
Cc: Zach Brown <zab@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/aio.c | 15 +++------------
1 file changed, 3 insertions(+), 12 deletions(-)
diff -puN fs/aio.c~aio-fix-kioctx-not-being-freed-after-cancellation-at-exit-time fs/aio.c
--- a/fs/aio.c~aio-fix-kioctx-not-being-freed-after-cancellation-at-exit-time
+++ a/fs/aio.c
@@ -349,7 +349,9 @@ static void free_ioctx(struct kioctx *ct
kunmap_atomic(ring);
while (atomic_read(&ctx->reqs_available) < ctx->nr_events - 1) {
- wait_event(ctx->wait, head != ctx->shadow_tail);
+ wait_event(ctx->wait,
+ (head != ctx->shadow_tail) ||
+ (atomic_read(&ctx->reqs_available) >= ctx->nr_events - 1));
avail = (head <= ctx->shadow_tail
? ctx->shadow_tail : ctx->nr_events) - head;
@@ -774,17 +776,6 @@ void batch_complete_aio(struct batch_com
n = rb_parent(n);
}
- if (unlikely(xchg(&req->ki_cancel,
- KIOCB_CANCELLED) == KIOCB_CANCELLED)) {
- /*
- * Can't use the percpu reqs_available here - could race
- * with free_ioctx()
- */
- atomic_inc(&req->ki_ctx->reqs_available);
- aio_put_req(req);
- continue;
- }
-
if (unlikely(req->ki_eventfd != eventfd)) {
if (eventfd) {
/* Make event visible */
_
Patches currently in -mm which might be from koverstreet@xxxxxxxxxx are
mm-remove-old-aio-use_mm-comment.patch
aio-remove-dead-code-from-aioh.patch
gadget-remove-only-user-of-aio-retry.patch
aio-remove-retry-based-aio.patch
char-add-aio_readwrite-to-dev-nullzero.patch
aio-kill-return-value-of-aio_complete.patch
aio-add-kiocb_cancel.patch
aio-move-private-stuff-out-of-aioh.patch
aio-dprintk-pr_debug.patch
aio-do-fget-after-aio_get_req.patch
aio-make-aio_put_req-lockless.patch
aio-refcounting-cleanup.patch
wait-add-wait_event_hrtimeout.patch
aio-make-aio_read_evt-more-efficient-convert-to-hrtimers.patch
aio-use-flush_dcache_page.patch
aio-use-cancellation-list-lazily.patch
aio-change-reqs_active-to-include-unreaped-completions.patch
aio-kill-batch-allocation.patch
aio-kill-struct-aio_ring_info.patch
aio-give-shared-kioctx-fields-their-own-cachelines.patch
aio-reqs_active-reqs_available.patch
aio-percpu-reqs_available.patch
generic-dynamic-per-cpu-refcounting.patch
aio-percpu-ioctx-refcount.patch
aio-use-xchg-instead-of-completion_lock.patch
aio-dont-include-aioh-in-schedh.patch
aio-kill-ki_key.patch
aio-kill-ki_retry.patch
block-prep-work-for-batch-completion.patch
block-aio-batch-completion-for-bios-kiocbs.patch
virtio-blk-convert-to-batch-completion.patch
mtip32xx-convert-to-batch-completion.patch
aio-fix-kioctx-not-being-freed-after-cancellation-at-exit-time.patch
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