include/net/dropreason.h | 67 ++++++++++++++++++++++++++++++++++++++ include/trace/events/skb.h | 15 ++++++++- net/core/.gitignore | 1 - net/core/Makefile | 22 +------------ net/core/skbuff.c | 6 +++- 5 files changed, 87 insertions(+), 24 deletions(-) delete mode 100644 net/core/.gitignore
From: Menglong Dong <imagedong@tencent.com>
As Eric reported, the 'reason' field is not presented when trace the
kfree_skb event by perf:
$ perf record -e skb:kfree_skb -a sleep 10
$ perf script
ip_defrag 14605 [021] 221.614303: skb:kfree_skb:
skbaddr=0xffff9d2851242700 protocol=34525 location=0xffffffffa39346b1
reason:
The cause seems to be passing kernel address directly to TP_printk(),
which is not right. As the enum 'skb_drop_reason' is not exported to
user space through TRACE_DEFINE_ENUM(), perf can't get the drop reason
string from the 'reason' field, which is a number.
Therefore, we introduce the macro DEFINE_DROP_REASON(), which is used
to define the trace enum by TRACE_DEFINE_ENUM(). With the help of
DEFINE_DROP_REASON(), now we can remove the auto-generate that we
introduced in the commit ec43908dd556
("net: skb: use auto-generation to convert skb drop reason to string"),
and define the string array 'drop_reasons'.
Hmmmm...now we come back to the situation that have to maintain drop
reasons in both enum skb_drop_reason and DEFINE_DROP_REASON. But they
are both in dropreason.h, which makes it easier.
After this commit, now the format of kfree_skb is like this:
$ cat /tracing/events/skb/kfree_skb/format
name: kfree_skb
ID: 1524
format:
field:unsigned short common_type; offset:0; size:2; signed:0;
field:unsigned char common_flags; offset:2; size:1; signed:0;
field:unsigned char common_preempt_count; offset:3; size:1; signed:0;
field:int common_pid; offset:4; size:4; signed:1;
field:void * skbaddr; offset:8; size:8; signed:0;
field:void * location; offset:16; size:8; signed:0;
field:unsigned short protocol; offset:24; size:2; signed:0;
field:enum skb_drop_reason reason; offset:28; size:4; signed:0;
print fmt: "skbaddr=%p protocol=%u location=%p reason: %s", REC->skbaddr, REC->protocol, REC->location, __print_symbolic(REC->reason, { 1, "NOT_SPECIFIED" }, { 2, "NO_SOCKET" } ......
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Menglong Dong <imagedong@tencent.com>
---
v2:
- undef FN/FNe after use it (Jakub Kicinski)
---
include/net/dropreason.h | 67 ++++++++++++++++++++++++++++++++++++++
include/trace/events/skb.h | 15 ++++++++-
net/core/.gitignore | 1 -
net/core/Makefile | 22 +------------
net/core/skbuff.c | 6 +++-
5 files changed, 87 insertions(+), 24 deletions(-)
delete mode 100644 net/core/.gitignore
diff --git a/include/net/dropreason.h b/include/net/dropreason.h
index fae9b40e54fa..c1cbcdbaf149 100644
--- a/include/net/dropreason.h
+++ b/include/net/dropreason.h
@@ -3,6 +3,73 @@
#ifndef _LINUX_DROPREASON_H
#define _LINUX_DROPREASON_H
+#define DEFINE_DROP_REASON(FN, FNe) \
+ FN(NOT_SPECIFIED) \
+ FN(NO_SOCKET) \
+ FN(PKT_TOO_SMALL) \
+ FN(TCP_CSUM) \
+ FN(SOCKET_FILTER) \
+ FN(UDP_CSUM) \
+ FN(NETFILTER_DROP) \
+ FN(OTHERHOST) \
+ FN(IP_CSUM) \
+ FN(IP_INHDR) \
+ FN(IP_RPFILTER) \
+ FN(UNICAST_IN_L2_MULTICAST) \
+ FN(XFRM_POLICY) \
+ FN(IP_NOPROTO) \
+ FN(SOCKET_RCVBUFF) \
+ FN(PROTO_MEM) \
+ FN(TCP_MD5NOTFOUND) \
+ FN(TCP_MD5UNEXPECTED) \
+ FN(TCP_MD5FAILURE) \
+ FN(SOCKET_BACKLOG) \
+ FN(TCP_FLAGS) \
+ FN(TCP_ZEROWINDOW) \
+ FN(TCP_OLD_DATA) \
+ FN(TCP_OVERWINDOW) \
+ FN(TCP_OFOMERGE) \
+ FN(TCP_RFC7323_PAWS) \
+ FN(TCP_INVALID_SEQUENCE) \
+ FN(TCP_RESET) \
+ FN(TCP_INVALID_SYN) \
+ FN(TCP_CLOSE) \
+ FN(TCP_FASTOPEN) \
+ FN(TCP_OLD_ACK) \
+ FN(TCP_TOO_OLD_ACK) \
+ FN(TCP_ACK_UNSENT_DATA) \
+ FN(TCP_OFO_QUEUE_PRUNE) \
+ FN(TCP_OFO_DROP) \
+ FN(IP_OUTNOROUTES) \
+ FN(BPF_CGROUP_EGRESS) \
+ FN(IPV6DISABLED) \
+ FN(NEIGH_CREATEFAIL) \
+ FN(NEIGH_FAILED) \
+ FN(NEIGH_QUEUEFULL) \
+ FN(NEIGH_DEAD) \
+ FN(TC_EGRESS) \
+ FN(QDISC_DROP) \
+ FN(CPU_BACKLOG) \
+ FN(XDP) \
+ FN(TC_INGRESS) \
+ FN(UNHANDLED_PROTO) \
+ FN(SKB_CSUM) \
+ FN(SKB_GSO_SEG) \
+ FN(SKB_UCOPY_FAULT) \
+ FN(DEV_HDR) \
+ FN(DEV_READY) \
+ FN(FULL_RING) \
+ FN(NOMEM) \
+ FN(HDR_TRUNC) \
+ FN(TAP_FILTER) \
+ FN(TAP_TXFILTER) \
+ FN(ICMP_CSUM) \
+ FN(INVALID_PROTO) \
+ FN(IP_INADDRERRORS) \
+ FN(IP_INNOROUTES) \
+ FN(PKT_TOO_BIG) \
+ FNe(MAX)
+
/**
* enum skb_drop_reason - the reasons of skb drops
*
diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h
index 45264e4bb254..50a974f7dfb4 100644
--- a/include/trace/events/skb.h
+++ b/include/trace/events/skb.h
@@ -9,6 +9,15 @@
#include <linux/netdevice.h>
#include <linux/tracepoint.h>
+#undef FN
+#define FN(reason) TRACE_DEFINE_ENUM(SKB_DROP_REASON_##reason);
+DEFINE_DROP_REASON(FN, FN)
+
+#undef FN
+#undef FNe
+#define FN(reason) { SKB_DROP_REASON_##reason, #reason },
+#define FNe(reason) { SKB_DROP_REASON_##reason, #reason }
+
/*
* Tracepoint for free an sk_buff:
*/
@@ -35,9 +44,13 @@ TRACE_EVENT(kfree_skb,
TP_printk("skbaddr=%p protocol=%u location=%p reason: %s",
__entry->skbaddr, __entry->protocol, __entry->location,
- drop_reasons[__entry->reason])
+ __print_symbolic(__entry->reason,
+ DEFINE_DROP_REASON(FN, FNe)))
);
+#undef FN
+#undef FNe
+
TRACE_EVENT(consume_skb,
TP_PROTO(struct sk_buff *skb),
diff --git a/net/core/.gitignore b/net/core/.gitignore
deleted file mode 100644
index df1e74372cce..000000000000
--- a/net/core/.gitignore
+++ /dev/null
@@ -1 +0,0 @@
-dropreason_str.c
diff --git a/net/core/Makefile b/net/core/Makefile
index e8ce3bd283a6..5857cec87b83 100644
--- a/net/core/Makefile
+++ b/net/core/Makefile
@@ -5,7 +5,7 @@
obj-y := sock.o request_sock.o skbuff.o datagram.o stream.o scm.o \
gen_stats.o gen_estimator.o net_namespace.o secure_seq.o \
- flow_dissector.o dropreason_str.o
+ flow_dissector.o
obj-$(CONFIG_SYSCTL) += sysctl_net_core.o
@@ -40,23 +40,3 @@ obj-$(CONFIG_NET_SOCK_MSG) += skmsg.o
obj-$(CONFIG_BPF_SYSCALL) += sock_map.o
obj-$(CONFIG_BPF_SYSCALL) += bpf_sk_storage.o
obj-$(CONFIG_OF) += of_net.o
-
-clean-files := dropreason_str.c
-
-quiet_cmd_dropreason_str = GEN $@
-cmd_dropreason_str = awk -F ',' 'BEGIN{ print "\#include <net/dropreason.h>\n"; \
- print "const char * const drop_reasons[] = {" }\
- /^enum skb_drop/ { dr=1; }\
- /^\};/ { dr=0; }\
- /^\tSKB_DROP_REASON_/ {\
- if (dr) {\
- sub(/\tSKB_DROP_REASON_/, "", $$1);\
- printf "\t[SKB_DROP_REASON_%s] = \"%s\",\n", $$1, $$1;\
- }\
- }\
- END{ print "};" }' $< > $@
-
-$(obj)/dropreason_str.c: $(srctree)/include/net/dropreason.h
- $(call cmd,dropreason_str)
-
-$(obj)/dropreason_str.o: $(obj)/dropreason_str.c
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 48ecfbf29174..f1b8b20fc20b 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -91,7 +91,11 @@ static struct kmem_cache *skbuff_ext_cache __ro_after_init;
int sysctl_max_skb_frags __read_mostly = MAX_SKB_FRAGS;
EXPORT_SYMBOL(sysctl_max_skb_frags);
-/* The array 'drop_reasons' is auto-generated in dropreason_str.c */
+#undef FN
+#define FN(reason) [SKB_DROP_REASON_##reason] = #reason,
+const char * const drop_reasons[] = {
+ DEFINE_DROP_REASON(FN, FN)
+};
EXPORT_SYMBOL(drop_reasons);
/**
--
2.37.2On Fri, Sep 2, 2022 at 7:18 AM <menglong8.dong@gmail.com> wrote:
>
> From: Menglong Dong <imagedong@tencent.com>
>
> As Eric reported, the 'reason' field is not presented when trace the
> kfree_skb event by perf:
>
> $ perf record -e skb:kfree_skb -a sleep 10
> $ perf script
> ip_defrag 14605 [021] 221.614303: skb:kfree_skb:
> skbaddr=0xffff9d2851242700 protocol=34525 location=0xffffffffa39346b1
> reason:
>
> The cause seems to be passing kernel address directly to TP_printk(),
> which is not right. As the enum 'skb_drop_reason' is not exported to
> user space through TRACE_DEFINE_ENUM(), perf can't get the drop reason
> string from the 'reason' field, which is a number.
>
> Therefore, we introduce the macro DEFINE_DROP_REASON(), which is used
> to define the trace enum by TRACE_DEFINE_ENUM(). With the help of
> DEFINE_DROP_REASON(), now we can remove the auto-generate that we
> introduced in the commit ec43908dd556
> ("net: skb: use auto-generation to convert skb drop reason to string"),
> and define the string array 'drop_reasons'.
>
> Hmmmm...now we come back to the situation that have to maintain drop
> reasons in both enum skb_drop_reason and DEFINE_DROP_REASON. But they
> are both in dropreason.h, which makes it easier.
>
> After this commit, now the format of kfree_skb is like this:
>
> $ cat /tracing/events/skb/kfree_skb/format
> name: kfree_skb
> ID: 1524
> format:
> field:unsigned short common_type; offset:0; size:2; signed:0;
> field:unsigned char common_flags; offset:2; size:1; signed:0;
> field:unsigned char common_preempt_count; offset:3; size:1; signed:0;
> field:int common_pid; offset:4; size:4; signed:1;
>
> field:void * skbaddr; offset:8; size:8; signed:0;
> field:void * location; offset:16; size:8; signed:0;
> field:unsigned short protocol; offset:24; size:2; signed:0;
> field:enum skb_drop_reason reason; offset:28; size:4; signed:0;
>
> print fmt: "skbaddr=%p protocol=%u location=%p reason: %s", REC->skbaddr, REC->protocol, REC->location, __print_symbolic(REC->reason, { 1, "NOT_SPECIFIED" }, { 2, "NO_SOCKET" } ......
>
> Reported-by: Eric Dumazet <edumazet@google.com>
Note that I also provided the sha1 of the faulty patch.
You should add a corresponding Fixes: tag, to help both humans and bots.
This would also hint that this patch should target net tree, not net-next ?
> Signed-off-by: Menglong Dong <imagedong@tencent.com>
> ---
> v2:
> - undef FN/FNe after use it (Jakub Kicinski)
I would love some feedback from Steven :)
On Fri, 2 Sep 2022 08:43:07 -0700
Eric Dumazet <edumazet@google.com> wrote:
> > ---
> > v2:
> > - undef FN/FNe after use it (Jakub Kicinski)
>
> I would love some feedback from Steven :)
The undef should be fine. I usually do not, but that's more of a preference
than a rule.
As long as the undef is done after the C portion of where the macro is used:
+#undef FN
+#define FN(reason) TRACE_DEFINE_ENUM(SKB_DROP_REASON_##reason);
+DEFINE_DROP_REASON(FN, FN) <<<--- C portion
+#undef FN
+#undef FNe
+#define FN(reason) { SKB_DROP_REASON_##reason, #reason },
+#define FNe(reason) { SKB_DROP_REASON_##reason, #reason }
+
/*
* Tracepoint for free an sk_buff:
*/
@@ -35,9 +44,13 @@ TRACE_EVENT(kfree_skb,
TP_printk("skbaddr=%p protocol=%u location=%p reason: %s",
__entry->skbaddr, __entry->protocol, __entry->location,
- drop_reasons[__entry->reason])
+ __print_symbolic(__entry->reason,
+ DEFINE_DROP_REASON(FN, FNe))) <<<--- C portion
);
+#undef FN
+#undef FNe
So for this part: Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
-- Steve
On Mon, Sep 5, 2022 at 7:37 AM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Fri, 2 Sep 2022 08:43:07 -0700
> Eric Dumazet <edumazet@google.com> wrote:
>
> > > ---
> > > v2:
> > > - undef FN/FNe after use it (Jakub Kicinski)
> >
> > I would love some feedback from Steven :)
>
> The undef should be fine. I usually do not, but that's more of a preference
> than a rule.
>
> As long as the undef is done after the C portion of where the macro is used:
>
> +#undef FN
> +#define FN(reason) TRACE_DEFINE_ENUM(SKB_DROP_REASON_##reason);
> +DEFINE_DROP_REASON(FN, FN) <<<--- C portion
>
> +#undef FN
> +#undef FNe
> +#define FN(reason) { SKB_DROP_REASON_##reason, #reason },
> +#define FNe(reason) { SKB_DROP_REASON_##reason, #reason }
> +
> /*
> * Tracepoint for free an sk_buff:
> */
> @@ -35,9 +44,13 @@ TRACE_EVENT(kfree_skb,
>
> TP_printk("skbaddr=%p protocol=%u location=%p reason: %s",
> __entry->skbaddr, __entry->protocol, __entry->location,
> - drop_reasons[__entry->reason])
> + __print_symbolic(__entry->reason,
> + DEFINE_DROP_REASON(FN, FNe))) <<<--- C portion
> );
>
> +#undef FN
> +#undef FNe
>
> So for this part: Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
>
> -- Steve
This seems broken again (tried on latest net-next tree)
perf script
sshd 12192 [006] 200.090602: skb:kfree_skb:
skbaddr=0x2fa000400000 protocol=7844 location=0x2fa000001ea4 reason:
swapper 0 [030] 200.497468: skb:kfree_skb:
skbaddr=0xba00400001 protocol=65535 location=0x9080c62800000000
reason:
kworker/30:1-ev 308 [030] 200.497476: skb:kfree_skb:
skbaddr=0xba00400001 protocol=65535 location=0x9080c62800000000
reason:
swapper 0 [009] 200.957881: skb:kfree_skb:
skbaddr=0x2fa400400000 protocol=12195 location=0x2fa400002fa3 reason:
swapper 0 [026] 201.515769: skb:kfree_skb:
skbaddr=0xb600400001 protocol=65535 location=0x9080c62800000000
reason:
kworker/26:1-mm 276 [026] 201.515797: skb:kfree_skb:
skbaddr=0xb600400001 protocol=65535 location=0x9080c62800000000
reason:
kworker/26:1-mm 276 [026] 201.515802: skb:kfree_skb:
skbaddr=0x2f9f00400000 protocol=12189 location=0x2f9f00002f9d reason:
swapper 0 [030] 201.521484: skb:kfree_skb:
skbaddr=0xba00400001 protocol=65535 location=0x9080c62800000000
reason:
kworker/30:1-ev 308 [030] 201.521491: skb:kfree_skb:
skbaddr=0x2fa100400000 protocol=12192 location=0x2fa100002fa0 reason:
On Thu, 27 Oct 2022 08:32:02 -0700 Eric Dumazet <edumazet@google.com> wrote: > This seems broken again (tried on latest net-next tree) > > perf script Do you also have the latest perf and the latest libtraceevent installed? -- Steve > sshd 12192 [006] 200.090602: skb:kfree_skb: > skbaddr=0x2fa000400000 protocol=7844 location=0x2fa000001ea4 reason: > swapper 0 [030] 200.497468: skb:kfree_skb: > skbaddr=0xba00400001 protocol=65535 location=0x9080c62800000000 > reason: > kworker/30:1-ev 308 [030] 200.497476: skb:kfree_skb: > skbaddr=0xba00400001 protocol=65535 location=0x9080c62800000000 > reason: > swapper 0 [009] 200.957881: skb:kfree_skb: > skbaddr=0x2fa400400000 protocol=12195 location=0x2fa400002fa3 reason: > swapper 0 [026] 201.515769: skb:kfree_skb: > skbaddr=0xb600400001 protocol=65535 location=0x9080c62800000000 > reason: > kworker/26:1-mm 276 [026] 201.515797: skb:kfree_skb: > skbaddr=0xb600400001 protocol=65535 location=0x9080c62800000000 > reason: > kworker/26:1-mm 276 [026] 201.515802: skb:kfree_skb: > skbaddr=0x2f9f00400000 protocol=12189 location=0x2f9f00002f9d reason: > swapper 0 [030] 201.521484: skb:kfree_skb: > skbaddr=0xba00400001 protocol=65535 location=0x9080c62800000000 > reason: > kworker/30:1-ev 308 [030] 201.521491: skb:kfree_skb: > skbaddr=0x2fa100400000 protocol=12192 location=0x2fa100002fa0 reason:
On Thu, Oct 27, 2022 at 8:43 AM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Thu, 27 Oct 2022 08:32:02 -0700
> Eric Dumazet <edumazet@google.com> wrote:
>
> > This seems broken again (tried on latest net-next tree)
> >
> > perf script
>
> Do you also have the latest perf and the latest libtraceevent installed?
>
I tried a more recent perf binary we have, but it is also not right.
I guess I will have to request a new perf binary at Google :/
perf5 script
swapper 0 [030] 4147.704606: skb:kfree_skb: [UNKNOWN EVENT]
kworker/30:1-ev 308 [030] 4147.704615: skb:kfree_skb: [UNKNOWN EVENT]
swapper 0 [030] 4148.048173: skb:kfree_skb: [UNKNOWN EVENT]
kworker/30:1-ev 308 [030] 4148.048179: skb:kfree_skb: [UNKNOWN EVENT]
swapper 0 [008] 4148.048773: skb:kfree_skb: [UNKNOWN EVENT]
swapper 0 [030] 4148.112271: skb:kfree_skb: [UNKNOWN EVENT]
kworker/30:1-ev 308 [030] 4148.112280: skb:kfree_skb: [UNKNOWN EVENT]
swapper 0 [030] 4148.720149: skb:kfree_skb: [UNKNOWN EVENT]
kworker/30:1-ev 308 [030] 4148.720155: skb:kfree_skb: [UNKNOWN EVENT]
swapper 0 [030] 4149.072141: skb:kfree_skb: [UNKNOWN EVENT]
kworker/30:1-ev 308 [030] 4149.072149: skb:kfree_skb: [UNKNOWN EVENT]
> On 2022/10/28 00:29，“Eric Dumazet”<edumazet@google.com> write:
>
> On Thu, Oct 27, 2022 at 8:43 AM Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> > On Thu, 27 Oct 2022 08:32:02 -0700
> > Eric Dumazet <edumazet@google.com> wrote:
> >
> > > This seems broken again (tried on latest net-next tree)
> > >
> > > perf script
> >
> > Do you also have the latest perf and the latest libtraceevent installed?
> >
>
> I tried a more recent perf binary we have, but it is also not right.
>
> I guess I will have to request a new perf binary at Google :/
>
Ennn...I just have a try, and it seems fine:
sudo perf script
swapper 0 [049] 401460.138078: skb:kfree_skb: skbaddr=0xffff8881076d2400 protocol=2048 location=0xffffffff81d86546 reason: TCP_INVALID_SEQUENCE
nc 429418 [006] 401465.652282: skb:kfree_skb: skbaddr=0xffff8881ea66cf00 protocol=0 location=0xffffffff81e0b48f reason: NOT_SPECIFIED
nc 429418 [006] 401465.652293: skb:kfree_skb: skbaddr=0xffff8881ea66cf00 protocol=0 location=0xffffffff81e0b48f reason: NOT_SPECIFIED
nc 429418 [006] 401465.652538: skb:kfree_skb: skbaddr=0xffff888133c014e8 protocol=2048 location=0xffffffff81d983a1 reason: NO_SOCKET
The version of the perf I used is 6.0.3-1:
sudo apt info linux-perf
Package: linux-perf
Version: 6.0.3-1
Thanks!
Menglong Dong
> perf5 script
> swapper 0 [030] 4147.704606: skb:kfree_skb: [UNKNOWN EVENT]
> kworker/30:1-ev 308 [030] 4147.704615: skb:kfree_skb: [UNKNOWN EVENT]
> swapper 0 [030] 4148.048173: skb:kfree_skb: [UNKNOWN EVENT]
> kworker/30:1-ev 308 [030] 4148.048179: skb:kfree_skb: [UNKNOWN EVENT]
> swapper 0 [008] 4148.048773: skb:kfree_skb: [UNKNOWN EVENT]
> swapper 0 [030] 4148.112271: skb:kfree_skb: [UNKNOWN EVENT]
> kworker/30:1-ev 308 [030] 4148.112280: skb:kfree_skb: [UNKNOWN EVENT]
> swapper 0 [030] 4148.720149: skb:kfree_skb: [UNKNOWN EVENT]
> kworker/30:1-ev 308 [030] 4148.720155: skb:kfree_skb: [UNKNOWN EVENT]
> swapper 0 [030] 4149.072141: skb:kfree_skb: [UNKNOWN EVENT]
> kworker/30:1-ev 308 [030] 4149.072149: skb:kfree_skb: [UNKNOWN EVENT]
On Thu, 27 Oct 2022 09:28:42 -0700 Eric Dumazet <edumazet@google.com> wrote: > I tried a more recent perf binary we have, but it is also not right. > > I guess I will have to request a new perf binary at Google :/ You could always use trace-cmd ;-) -- Steve
On Fri, Sep 2, 2022 at 11:43 PM Eric Dumazet <edumazet@google.com> wrote:
>
> On Fri, Sep 2, 2022 at 7:18 AM <menglong8.dong@gmail.com> wrote:
> >
> > From: Menglong Dong <imagedong@tencent.com>
> >
> > As Eric reported, the 'reason' field is not presented when trace the
> > kfree_skb event by perf:
> >
> > $ perf record -e skb:kfree_skb -a sleep 10
> > $ perf script
> > ip_defrag 14605 [021] 221.614303: skb:kfree_skb:
> > skbaddr=0xffff9d2851242700 protocol=34525 location=0xffffffffa39346b1
> > reason:
> >
> > The cause seems to be passing kernel address directly to TP_printk(),
> > which is not right. As the enum 'skb_drop_reason' is not exported to
> > user space through TRACE_DEFINE_ENUM(), perf can't get the drop reason
> > string from the 'reason' field, which is a number.
> >
> > Therefore, we introduce the macro DEFINE_DROP_REASON(), which is used
> > to define the trace enum by TRACE_DEFINE_ENUM(). With the help of
> > DEFINE_DROP_REASON(), now we can remove the auto-generate that we
> > introduced in the commit ec43908dd556
> > ("net: skb: use auto-generation to convert skb drop reason to string"),
> > and define the string array 'drop_reasons'.
> >
> > Hmmmm...now we come back to the situation that have to maintain drop
> > reasons in both enum skb_drop_reason and DEFINE_DROP_REASON. But they
> > are both in dropreason.h, which makes it easier.
> >
> > After this commit, now the format of kfree_skb is like this:
> >
> > $ cat /tracing/events/skb/kfree_skb/format
> > name: kfree_skb
> > ID: 1524
> > format:
> > field:unsigned short common_type; offset:0; size:2; signed:0;
> > field:unsigned char common_flags; offset:2; size:1; signed:0;
> > field:unsigned char common_preempt_count; offset:3; size:1; signed:0;
> > field:int common_pid; offset:4; size:4; signed:1;
> >
> > field:void * skbaddr; offset:8; size:8; signed:0;
> > field:void * location; offset:16; size:8; signed:0;
> > field:unsigned short protocol; offset:24; size:2; signed:0;
> > field:enum skb_drop_reason reason; offset:28; size:4; signed:0;
> >
> > print fmt: "skbaddr=%p protocol=%u location=%p reason: %s", REC->skbaddr, REC->protocol, REC->location, __print_symbolic(REC->reason, { 1, "NOT_SPECIFIED" }, { 2, "NO_SOCKET" } ......
> >
> > Reported-by: Eric Dumazet <edumazet@google.com>
>
> Note that I also provided the sha1 of the faulty patch.
>
> You should add a corresponding Fixes: tag, to help both humans and bots.
>
Okay, I'll add the Fixes tag......and the Link tag.
> This would also hint that this patch should target net tree, not net-next ?
>
It seems that the net tree is more suitable. I'll change it.
Thanks!
> > Signed-off-by: Menglong Dong <imagedong@tencent.com>
> > ---
> > v2:
> > - undef FN/FNe after use it (Jakub Kicinski)
>
> I would love some feedback from Steven :)
Hi, Steven! Do you have any feedback? Yes, I add the
TRACE_DEFINE_ENUM() back! (Hmm...I deleted it before,
without knowing its function :/ )
Thanks!
Menglong Dong
© 2016 - 2026 Red Hat, Inc.