diff options
| author | Jesper Dangaard Brouer <brouer@redhat.com> | 2020-05-14 12:49:33 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-05-14 21:21:54 -0700 |
| commit | 34cc0b338a61de3eee3a2bfcaf4f9d6e9fae091a (patch) | |
| tree | fb51ed98a7080db136df2260b9de579b645482ef /net/core | |
| parent | a075767bbdc659066b89be282c8377fa880e9dc4 (diff) | |
xdp: Xdp_frame add member frame_sz and handle in convert_to_xdp_frame
Use hole in struct xdp_frame, when adding member frame_sz, which keeps
same sizeof struct (32 bytes)
Drivers ixgbe and sfc had bug cases where the necessary/expected
tailroom was not reserved. This can lead to some hard to catch memory
corruption issues. Having the drivers frame_sz this can be detected when
packet length/end via xdp->data_end exceed the xdp_data_hard_end
pointer, which accounts for the reserved the tailroom.
When detecting this driver issue, simply fail the conversion with NULL,
which results in feedback to driver (failing xdp_do_redirect()) causing
driver to drop packet. Given the lack of consistent XDP stats, this can
be hard to troubleshoot. And given this is a driver bug, we want to
generate some more noise in form of a WARN stack dump (to ID the driver
code that inlined convert_to_xdp_frame).
Inlining the WARN macro is problematic, because it adds an asm
instruction (on Intel CPUs ud2) what influence instruction cache
prefetching. Thus, introduce xdp_warn and macro XDP_WARN, to avoid this
and at the same time make identifying the function and line of this
inlined function easier.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/158945337313.97035.10015729316710496600.stgit@firesoul
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/xdp.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/net/core/xdp.c b/net/core/xdp.c index 4c7ea85486af..490b8f5fa8ee 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -11,6 +11,7 @@ #include <linux/slab.h> #include <linux/idr.h> #include <linux/rhashtable.h> +#include <linux/bug.h> #include <net/page_pool.h> #include <net/xdp.h> @@ -496,3 +497,10 @@ struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp) return xdpf; } EXPORT_SYMBOL_GPL(xdp_convert_zc_to_xdp_frame); + +/* Used by XDP_WARN macro, to avoid inlining WARN() in fast-path */ +void xdp_warn(const char *msg, const char *func, const int line) +{ + WARN(1, "XDP_WARN: %s(line:%d): %s\n", func, line, msg); +}; +EXPORT_SYMBOL_GPL(xdp_warn); |