From 6032ebb54c60cae24329f6aba3ce0c1ca8ad6abe Mon Sep 17 00:00:00 2001 From: Pedro Tammela Date: Thu, 25 Mar 2021 12:01:15 -0300 Subject: libbpf: Fix bail out from 'ringbuf_process_ring()' on error The current code bails out with negative and positive returns. If the callback returns a positive return code, 'ring_buffer__consume()' and 'ring_buffer__poll()' will return a spurious number of records consumed, but mostly important will continue the processing loop. This patch makes positive returns from the callback a no-op. Fixes: bf99c936f947 ("libbpf: Add BPF ring buffer support") Signed-off-by: Pedro Tammela Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210325150115.138750-1-pctammela@mojatatu.com --- tools/lib/bpf/ringbuf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c index 8caaafe7e312..e7a8d847161f 100644 --- a/tools/lib/bpf/ringbuf.c +++ b/tools/lib/bpf/ringbuf.c @@ -227,7 +227,7 @@ static int ringbuf_process_ring(struct ring* r) if ((len & BPF_RINGBUF_DISCARD_BIT) == 0) { sample = (void *)len_ptr + BPF_RINGBUF_HDR_SZ; err = r->sample_cb(r->ctx, sample, len); - if (err) { + if (err < 0) { /* update consumer pos and bail out */ smp_store_release(r->consumer_pos, cons_pos); -- cgit v1.2.3 From df662016310aa4475d7986fd726af45c8fe4f362 Mon Sep 17 00:00:00 2001 From: Ciara Loftus Date: Wed, 31 Mar 2021 06:12:16 +0000 Subject: libbpf: Ensure umem pointer is non-NULL before dereferencing Calls to xsk_socket__create dereference the umem to access the fill_save and comp_save pointers. Make sure the umem is non-NULL before doing this. Fixes: 2f6324a3937f ("libbpf: Support shared umems between queues and devices") Signed-off-by: Ciara Loftus Signed-off-by: Alexei Starovoitov Acked-by: Magnus Karlsson Link: https://lore.kernel.org/bpf/20210331061218.1647-2-ciara.loftus@intel.com --- tools/lib/bpf/xsk.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'tools/lib') diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index 526fc35c0b23..443b0cfb45e8 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -1019,6 +1019,9 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname, struct xsk_ring_cons *rx, struct xsk_ring_prod *tx, const struct xsk_socket_config *usr_config) { + if (!umem) + return -EFAULT; + return xsk_socket__create_shared(xsk_ptr, ifname, queue_id, umem, rx, tx, umem->fill_save, umem->comp_save, usr_config); -- cgit v1.2.3 From 43f1bc1efff16f553dd573d02eb7a15750925568 Mon Sep 17 00:00:00 2001 From: Ciara Loftus Date: Wed, 31 Mar 2021 06:12:17 +0000 Subject: libbpf: Restore umem state after socket create failure If the call to xsk_socket__create fails, the user may want to retry the socket creation using the same umem. Ensure that the umem is in the same state on exit if the call fails by: 1. ensuring the umem _save pointers are unmodified. 2. not unmapping the set of umem rings that were set up with the umem during xsk_umem__create, since those maps existed before the call to xsk_socket__create and should remain in tact even in the event of failure. Fixes: 2f6324a3937f ("libbpf: Support shared umems between queues and devices") Signed-off-by: Ciara Loftus Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20210331061218.1647-3-ciara.loftus@intel.com --- tools/lib/bpf/xsk.c | 41 +++++++++++++++++++++++------------------ 1 file changed, 23 insertions(+), 18 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index 443b0cfb45e8..5098d9e3b55a 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -743,26 +743,30 @@ static struct xsk_ctx *xsk_get_ctx(struct xsk_umem *umem, int ifindex, return NULL; } -static void xsk_put_ctx(struct xsk_ctx *ctx) +static void xsk_put_ctx(struct xsk_ctx *ctx, bool unmap) { struct xsk_umem *umem = ctx->umem; struct xdp_mmap_offsets off; int err; - if (--ctx->refcount == 0) { - err = xsk_get_mmap_offsets(umem->fd, &off); - if (!err) { - munmap(ctx->fill->ring - off.fr.desc, - off.fr.desc + umem->config.fill_size * - sizeof(__u64)); - munmap(ctx->comp->ring - off.cr.desc, - off.cr.desc + umem->config.comp_size * - sizeof(__u64)); - } + if (--ctx->refcount) + return; - list_del(&ctx->list); - free(ctx); - } + if (!unmap) + goto out_free; + + err = xsk_get_mmap_offsets(umem->fd, &off); + if (err) + goto out_free; + + munmap(ctx->fill->ring - off.fr.desc, off.fr.desc + umem->config.fill_size * + sizeof(__u64)); + munmap(ctx->comp->ring - off.cr.desc, off.cr.desc + umem->config.comp_size * + sizeof(__u64)); + +out_free: + list_del(&ctx->list); + free(ctx); } static struct xsk_ctx *xsk_create_ctx(struct xsk_socket *xsk, @@ -797,8 +801,6 @@ static struct xsk_ctx *xsk_create_ctx(struct xsk_socket *xsk, memcpy(ctx->ifname, ifname, IFNAMSIZ - 1); ctx->ifname[IFNAMSIZ - 1] = '\0'; - umem->fill_save = NULL; - umem->comp_save = NULL; ctx->fill = fill; ctx->comp = comp; list_add(&ctx->list, &umem->ctx_list); @@ -854,6 +856,7 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, struct xsk_socket *xsk; struct xsk_ctx *ctx; int err, ifindex; + bool unmap = umem->fill_save != fill; if (!umem || !xsk_ptr || !(rx || tx)) return -EFAULT; @@ -994,6 +997,8 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, } *xsk_ptr = xsk; + umem->fill_save = NULL; + umem->comp_save = NULL; return 0; out_mmap_tx: @@ -1005,7 +1010,7 @@ out_mmap_rx: munmap(rx_map, off.rx.desc + xsk->config.rx_size * sizeof(struct xdp_desc)); out_put_ctx: - xsk_put_ctx(ctx); + xsk_put_ctx(ctx, unmap); out_socket: if (--umem->refcount) close(xsk->fd); @@ -1071,7 +1076,7 @@ void xsk_socket__delete(struct xsk_socket *xsk) } } - xsk_put_ctx(ctx); + xsk_put_ctx(ctx, true); umem->refcount--; /* Do not close an fd that also has an associated umem connected -- cgit v1.2.3 From ca7a83e2487ad0bc9a3e0e7a8645354aa1782f13 Mon Sep 17 00:00:00 2001 From: Ciara Loftus Date: Wed, 31 Mar 2021 06:12:18 +0000 Subject: libbpf: Only create rx and tx XDP rings when necessary Prior to this commit xsk_socket__create(_shared) always attempted to create the rx and tx rings for the socket. However this causes an issue when the socket being setup is that which shares the fd with the UMEM. If a previous call to this function failed with this socket after the rings were set up, a subsequent call would always fail because the rings are not torn down after the first call and when we try to set them up again we encounter an error because they already exist. Solve this by remembering whether the rings were set up by introducing new bools to struct xsk_umem which represent the ring setup status and using them to determine whether or not to set up the rings. Fixes: 1cad07884239 ("libbpf: add support for using AF_XDP sockets") Signed-off-by: Ciara Loftus Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20210331061218.1647-4-ciara.loftus@intel.com --- tools/lib/bpf/xsk.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index 5098d9e3b55a..d24b5cc720ec 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -59,6 +59,8 @@ struct xsk_umem { int fd; int refcount; struct list_head ctx_list; + bool rx_ring_setup_done; + bool tx_ring_setup_done; }; struct xsk_ctx { @@ -857,6 +859,7 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, struct xsk_ctx *ctx; int err, ifindex; bool unmap = umem->fill_save != fill; + bool rx_setup_done = false, tx_setup_done = false; if (!umem || !xsk_ptr || !(rx || tx)) return -EFAULT; @@ -884,6 +887,8 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, } } else { xsk->fd = umem->fd; + rx_setup_done = umem->rx_ring_setup_done; + tx_setup_done = umem->tx_ring_setup_done; } ctx = xsk_get_ctx(umem, ifindex, queue_id); @@ -902,7 +907,7 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, } xsk->ctx = ctx; - if (rx) { + if (rx && !rx_setup_done) { err = setsockopt(xsk->fd, SOL_XDP, XDP_RX_RING, &xsk->config.rx_size, sizeof(xsk->config.rx_size)); @@ -910,8 +915,10 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, err = -errno; goto out_put_ctx; } + if (xsk->fd == umem->fd) + umem->rx_ring_setup_done = true; } - if (tx) { + if (tx && !tx_setup_done) { err = setsockopt(xsk->fd, SOL_XDP, XDP_TX_RING, &xsk->config.tx_size, sizeof(xsk->config.tx_size)); @@ -919,6 +926,8 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, err = -errno; goto out_put_ctx; } + if (xsk->fd == umem->fd) + umem->rx_ring_setup_done = true; } err = xsk_get_mmap_offsets(xsk->fd, &off); -- cgit v1.2.3