| Message ID | fee2452494222ecc7f1f88c8fb659baef971414a.1655852245.git.asml.silence@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | poll fixes | expand |
On 6/21/22 5:00 PM, Pavel Begunkov wrote: > We have re-polling for partial IO, so a request can be polled twice. If > it used two poll entries the first time then on the second > io_arm_poll_handler() it will find the old apoll entry and NULL > kmalloc()'ed second entry, i.e. apoll->double_poll, so leaking it. > > Fixes: 10c873334feba ("io_uring: allow re-poll if we made progress") > Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> > --- > fs/io_uring.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/fs/io_uring.c b/fs/io_uring.c > index cb719a53b8bd..5c95755619e2 100644 > --- a/fs/io_uring.c > +++ b/fs/io_uring.c > @@ -7208,6 +7208,7 @@ static int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags) > mask |= EPOLLEXCLUSIVE; > if (req->flags & REQ_F_POLLED) { > apoll = req->apoll; > + kfree(apoll->double_poll); > } else if (!(issue_flags & IO_URING_F_UNLOCKED) && > !list_empty(&ctx->apoll_cache)) { > apoll = list_first_entry(&ctx->apoll_cache, struct async_poll, Looks good, my only question was on whether we should clear ->double_poll here, but we do that right below so all's good.
diff --git a/fs/io_uring.c b/fs/io_uring.c index cb719a53b8bd..5c95755619e2 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -7208,6 +7208,7 @@ static int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags) mask |= EPOLLEXCLUSIVE; if (req->flags & REQ_F_POLLED) { apoll = req->apoll; + kfree(apoll->double_poll); } else if (!(issue_flags & IO_URING_F_UNLOCKED) && !list_empty(&ctx->apoll_cache)) { apoll = list_first_entry(&ctx->apoll_cache, struct async_poll,
We have re-polling for partial IO, so a request can be polled twice. If it used two poll entries the first time then on the second io_arm_poll_handler() it will find the old apoll entry and NULL kmalloc()'ed second entry, i.e. apoll->double_poll, so leaking it. Fixes: 10c873334feba ("io_uring: allow re-poll if we made progress") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> --- fs/io_uring.c | 1 + 1 file changed, 1 insertion(+)