[PATCH bpf-next] selftests/bpf: Replace %pK output with 0

[PATCH bpf-next] selftests/bpf: Replace %pK output with 0

[Sebastian Andrzej Siewior]

Networking used to print the socket pointer with %p as output in the
/proc interface. This was later changed to %pK in order not to reveal
the actual pointer value. The output format has then been copied to bpf
tests which produce the same format including the %pK format modifier.

Networking recently replaced the socket output with a plain 0 because
the socket pointer added no value to the output and the %pK should be
removed fom library handling. The format remained otherwise unchanged in
order not to break any tools which are parsing this information.

This change removes the %pK modifier from bpf, following the change in
networking.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---

The networking change is in net-next as commit 7c0ec6288b497 ("net:
Replace %pK output with 0")

 tools/testing/selftests/bpf/README.rst               |  2 +-
 tools/testing/selftests/bpf/prog_tests/snprintf.c    |  2 +-
 tools/testing/selftests/bpf/progs/bpf_iter_netlink.c |  4 ++--
 tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c    | 11 +++++------
 tools/testing/selftests/bpf/progs/bpf_iter_tcp6.c    | 11 +++++------
 tools/testing/selftests/bpf/progs/bpf_iter_udp4.c    |  4 ++--
 tools/testing/selftests/bpf/progs/bpf_iter_udp6.c    |  4 ++--
 tools/testing/selftests/bpf/progs/bpf_iter_unix.c    |  3 +--
 tools/testing/selftests/bpf/progs/test_snprintf.c    |  4 ++--
 9 files changed, 21 insertions(+), 24 deletions(-)

diff --git a/tools/testing/selftests/bpf/README.rst b/tools/testing/selftests/bpf/README.rst
index 07c834433b388..75ff1142c1857 100644
--- a/tools/testing/selftests/bpf/README.rst
+++ b/tools/testing/selftests/bpf/README.rst
@@ -187,7 +187,7 @@ The symptom for ``bpf_iter/netlink`` looks like
   ...
   15: (bf) r2 = r7
   16: (0f) r2 += r1
-  ; BPF_SEQ_PRINTF(seq, "%pK %-3d ", s, s->sk_protocol);
+  ; BPF_SEQ_PRINTF(seq, "%p %-3d ", s, s->sk_protocol);
   17: (7b) *(u64 *)(r7 +0) = r2
   only read is supported
 
diff --git a/tools/testing/selftests/bpf/prog_tests/snprintf.c b/tools/testing/selftests/bpf/prog_tests/snprintf.c
index 4e4a82d54f799..f2cd442c4683c 100644
--- a/tools/testing/selftests/bpf/prog_tests/snprintf.c
+++ b/tools/testing/selftests/bpf/prog_tests/snprintf.c
@@ -16,7 +16,7 @@
 #define MIN_SYM_RET  sizeof(EXP_SYM_OUT)
 
 /* The third specifier, %p, is a hashed pointer which changes on every reboot */
-#define EXP_ADDR_OUT "0000000000000000 ffff00000add4e55 "
+#define EXP_ADDR_OUT "ffff00000add4e55 "
 #define EXP_ADDR_RET sizeof(EXP_ADDR_OUT "unknownhashedptr")
 
 #define EXP_STR_OUT  "str1         a  b c      d e longstr"
diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_netlink.c b/tools/testing/selftests/bpf/progs/bpf_iter_netlink.c
index 00b2ceae81fb0..b9107d3ab6039 100644
--- a/tools/testing/selftests/bpf/progs/bpf_iter_netlink.c
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_netlink.c
@@ -25,12 +25,12 @@ int dump_netlink(struct bpf_iter__netlink *ctx)
 		return 0;
 
 	if (ctx->meta->seq_num == 0)
-		BPF_SEQ_PRINTF(seq, "sk               Eth Pid        Groups   "
+		BPF_SEQ_PRINTF(seq, "sk Eth Pid        Groups   "
 				    "Rmem     Wmem     Dump  Locks    Drops    "
 				    "Inode\n");
 
 	s = &nlk->sk;
-	BPF_SEQ_PRINTF(seq, "%pK %-3d ", s, s->sk_protocol);
+	BPF_SEQ_PRINTF(seq, "0  %-3d ", s->sk_protocol);
 
 	if (!nlk->groups)  {
 		group = 0;
diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c b/tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c
index b1e509b231cd9..d149cf0d07be6 100644
--- a/tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c
@@ -131,8 +131,7 @@ static int dump_tcp_sock(struct seq_file *seq, struct tcp_sock *tp,
 		       icsk->icsk_probes_out,
 		       sock_i_ino(sp),
 		       sp->sk_refcnt.refs.counter);
-	BPF_SEQ_PRINTF(seq, "%pK %lu %lu %u %u %d\n",
-		       tp,
+	BPF_SEQ_PRINTF(seq, "0 %lu %lu %u %u %d\n",
 		       jiffies_to_clock_t(icsk->icsk_rto),
 		       jiffies_to_clock_t(icsk->icsk_ack.ato),
 		       (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(icsk),
@@ -161,10 +160,10 @@ static int dump_tw_sock(struct seq_file *seq, struct tcp_timewait_sock *ttw,
 	BPF_SEQ_PRINTF(seq, "%4d: %08X:%04X %08X:%04X ",
 		       seq_num, src, srcp, dest, destp);
 
-	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
+	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d 0\n",
 		       tw->tw_substate, 0, 0,
 		       3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
-		       tw->tw_refcnt.refs.counter, tw);
+		       tw->tw_refcnt.refs.counter);
 
 	return 0;
 }
@@ -185,9 +184,9 @@ static int dump_req_sock(struct seq_file *seq, struct tcp_request_sock *treq,
 		       seq_num, irsk->ir_loc_addr,
 		       irsk->ir_num, irsk->ir_rmt_addr,
 		       bpf_ntohs(irsk->ir_rmt_port));
-	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
+	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d 0\n",
 		       TCP_SYN_RECV, 0, 0, 1, jiffies_to_clock_t(ttd),
-		       req->num_timeout, uid, 0, 0, 0, req);
+		       req->num_timeout, uid, 0, 0, 0);
 
 	return 0;
 }
diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_tcp6.c b/tools/testing/selftests/bpf/progs/bpf_iter_tcp6.c
index dbc7166aee91f..cd65fa81f1219 100644
--- a/tools/testing/selftests/bpf/progs/bpf_iter_tcp6.c
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_tcp6.c
@@ -135,8 +135,7 @@ static int dump_tcp6_sock(struct seq_file *seq, struct tcp6_sock *tp,
 		       icsk->icsk_probes_out,
 		       sock_i_ino(sp),
 		       sp->sk_refcnt.refs.counter);
-	BPF_SEQ_PRINTF(seq, "%pK %lu %lu %u %u %d\n",
-		       tp,
+	BPF_SEQ_PRINTF(seq, "0 %lu %lu %u %u %d\n",
 		       jiffies_to_clock_t(icsk->icsk_rto),
 		       jiffies_to_clock_t(icsk->icsk_ack.ato),
 		       (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(icsk),
@@ -170,10 +169,10 @@ static int dump_tw_sock(struct seq_file *seq, struct tcp_timewait_sock *ttw,
 		       dest->s6_addr32[0], dest->s6_addr32[1],
 		       dest->s6_addr32[2], dest->s6_addr32[3], destp);
 
-	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
+	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d 0\n",
 		       tw->tw_substate, 0, 0,
 		       3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
-		       tw->tw_refcnt.refs.counter, tw);
+		       tw->tw_refcnt.refs.counter);
 
 	return 0;
 }
@@ -201,9 +200,9 @@ static int dump_req_sock(struct seq_file *seq, struct tcp_request_sock *treq,
 		       dest->s6_addr32[0], dest->s6_addr32[1],
 		       dest->s6_addr32[2], dest->s6_addr32[3],
 		       bpf_ntohs(irsk->ir_rmt_port));
-	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
+	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d 0\n",
 		       TCP_SYN_RECV, 0, 0, 1, jiffies_to_clock_t(ttd),
-		       req->num_timeout, uid, 0, 0, 0, req);
+		       req->num_timeout, uid, 0, 0, 0);
 
 	return 0;
 }
diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_udp4.c b/tools/testing/selftests/bpf/progs/bpf_iter_udp4.c
index 23b2aa2604de2..9b789f09f1462 100644
--- a/tools/testing/selftests/bpf/progs/bpf_iter_udp4.c
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_udp4.c
@@ -57,13 +57,13 @@ int dump_udp4(struct bpf_iter__udp *ctx)
 	BPF_SEQ_PRINTF(seq, "%5d: %08X:%04X %08X:%04X ",
 		       ctx->bucket, src, srcp, dest, destp);
 
-	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u\n",
+	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %8d %u\n",
 		       inet->sk.sk_state,
 		       inet->sk.sk_wmem_alloc.refs.counter - 1,
 		       rqueue,
 		       0, 0L, 0, ctx->uid, 0,
 		       sock_i_ino(&inet->sk),
-		       inet->sk.sk_refcnt.refs.counter, udp_sk,
+		       inet->sk.sk_refcnt.refs.counter, 0,
 		       udp_sk->drop_counters.drops0.counter +
 		       udp_sk->drop_counters.drops1.counter);
 
diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_udp6.c b/tools/testing/selftests/bpf/progs/bpf_iter_udp6.c
index c48b05aa2a4b2..9766eff7069ff 100644
--- a/tools/testing/selftests/bpf/progs/bpf_iter_udp6.c
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_udp6.c
@@ -65,13 +65,13 @@ int dump_udp6(struct bpf_iter__udp *ctx)
 		       dest->s6_addr32[0], dest->s6_addr32[1],
 		       dest->s6_addr32[2], dest->s6_addr32[3], destp);
 
-	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u\n",
+	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %8d %u\n",
 		       inet->sk.sk_state,
 		       inet->sk.sk_wmem_alloc.refs.counter - 1,
 		       rqueue,
 		       0, 0L, 0, ctx->uid, 0,
 		       sock_i_ino(&inet->sk),
-		       inet->sk.sk_refcnt.refs.counter, udp_sk,
+		       inet->sk.sk_refcnt.refs.counter, 0,
 		       udp_sk->drop_counters.drops0.counter +
 		       udp_sk->drop_counters.drops1.counter);
 	return 0;
diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_unix.c b/tools/testing/selftests/bpf/progs/bpf_iter_unix.c
index a2652c8c3616f..36690478992f8 100644
--- a/tools/testing/selftests/bpf/progs/bpf_iter_unix.c
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_unix.c
@@ -44,8 +44,7 @@ int dump_unix(struct bpf_iter__unix *ctx)
 	if (seq_num == 0)
 		BPF_SEQ_PRINTF(seq, "Num               RefCount Protocol Flags    Type St    Inode Path\n");
 
-	BPF_SEQ_PRINTF(seq, "%pK: %08X %08X %08X %04X %02X %8lu",
-		       unix_sk,
+	BPF_SEQ_PRINTF(seq, "%08u: %08X %08X %08X %04X %02X %8lu", 0,
 		       sk->sk_refcnt.refs.counter,
 		       0,
 		       sk->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
diff --git a/tools/testing/selftests/bpf/progs/test_snprintf.c b/tools/testing/selftests/bpf/progs/test_snprintf.c
index 8fda075440235..48a0025cf2ca8 100644
--- a/tools/testing/selftests/bpf/progs/test_snprintf.c
+++ b/tools/testing/selftests/bpf/progs/test_snprintf.c
@@ -57,8 +57,8 @@ int handler(const void *ctx)
 	sym_ret  = BPF_SNPRINTF(sym_out,  sizeof(sym_out), "%ps %pS %pB",
 				&schedule, &schedule, &schedule);
 	/* Kernel pointers */
-	addr_ret = BPF_SNPRINTF(addr_out, sizeof(addr_out), "%pK %px %p",
-				0, 0xFFFF00000ADD4E55, 0xFFFF00000ADD4E55);
+	addr_ret = BPF_SNPRINTF(addr_out, sizeof(addr_out), "%px %p",
+				0xFFFF00000ADD4E55, 0xFFFF00000ADD4E55);
 	/* Strings and single-byte character embedding */
 	str_ret  = BPF_SNPRINTF(str_out, sizeof(str_out), "%s % 9c %+2c %-3c %04c %0c %+05s",
 				str1, 'a', 'b', 'c', 'd', 'e', longstr);
-- 
2.55.0

Re: [PATCH bpf-next] selftests/bpf: Replace %pK output with 0

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Incorrect replacement of `%pK` with padded format specifier `%8d` for UDP sockets causes a mismatch with native `/proc/net/` output.
--

commit c1f7209e53e018927a70341e583a110e2a63d48e
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

selftests/bpf: Replace %pK output with 0

This commit replaces the %pK format modifier with 0 in BPF iterator tests to
match a recent change in the networking subsystem. The socket pointers are
removed from the output formatting to align with native /proc/net/ interfaces.

> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_udp4.c b/tools/testing/selftests/bpf/progs/bpf_iter_udp4.c
> index 23b2aa2604de2..9b789f09f1462 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_udp4.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_udp4.c
> @@ -57,13 +57,13 @@ int dump_udp4(struct bpf_iter__udp *ctx)
>  	BPF_SEQ_PRINTF(seq, "%5d: %08X:%04X %08X:%04X ",
>  		       ctx->bucket, src, srcp, dest, destp);
>  
> -	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u\n",
> +	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %8d %u\n",

[Severity: Low]
Does this %8d format incorrectly pad the 0 with spaces?

The networking subsystem replaced %pK with a literal 0, but replacing it with
%8d here in dump_udp4() causes a mismatch with the native /proc/net/ output.
Since BPF iterators are designed as exact drop-in replacements, could this
mismatch break parsers that rely on strict spacing?

[ ... ]

> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_udp6.c b/tools/testing/selftests/bpf/progs/bpf_iter_udp6.c
> index c48b05aa2a4b2..9766eff7069ff 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_udp6.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_udp6.c
> @@ -65,13 +65,13 @@ int dump_udp6(struct bpf_iter__udp *ctx)
>  		       dest->s6_addr32[0], dest->s6_addr32[1],
>  		       dest->s6_addr32[2], dest->s6_addr32[3], destp);
>  
> -	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u\n",
> +	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %8d %u\n",

[Severity: Low]
Is the use of %8d here in dump_udp6() introducing the same formatting
mismatch as in dump_udp4()?

It seems it should use a literal 0 instead of %8d to exactly match the
networking subsystem's native output format.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260911145011.kErTVDkS@linutronix.de?part=1

Re: [PATCH bpf-next] selftests/bpf: Replace %pK output with 0

[Sebastian Andrzej Siewior]

On 2026-09-11 15:03:37 [+0000], sashiko-bot@kernel.org wrote:
> > diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_udp4.c b/tools/testing/selftests/bpf/progs/bpf_iter_udp4.c
> > index 23b2aa2604de2..9b789f09f1462 100644
> > --- a/tools/testing/selftests/bpf/progs/bpf_iter_udp4.c
> > +++ b/tools/testing/selftests/bpf/progs/bpf_iter_udp4.c
> > @@ -57,13 +57,13 @@ int dump_udp4(struct bpf_iter__udp *ctx)
> >  	BPF_SEQ_PRINTF(seq, "%5d: %08X:%04X %08X:%04X ",
> >  		       ctx->bucket, src, srcp, dest, destp);
> >  
> > -	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u\n",
> > +	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %8d %u\n",
> 
> [Severity: Low]
> Does this %8d format incorrectly pad the 0 with spaces?
> 
> The networking subsystem replaced %pK with a literal 0, but replacing it with
> %8d here in dump_udp4() causes a mismatch with the native /proc/net/ output.
> Since BPF iterators are designed as exact drop-in replacements, could this
> mismatch break parsers that rely on strict spacing?

Indeed. I tried to match the pointer spacing for some reason. The
formatting in net does not align with the columns starting with the
inode which is %lu instead having 5 width same goes for ref. So I just
ignored and moved on with a plain 0. I could update if this is
considered important.

> [ ... ]
> 
> > diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_udp6.c b/tools/testing/selftests/bpf/progs/bpf_iter_udp6.c
> > index c48b05aa2a4b2..9766eff7069ff 100644
> > --- a/tools/testing/selftests/bpf/progs/bpf_iter_udp6.c
> > +++ b/tools/testing/selftests/bpf/progs/bpf_iter_udp6.c
> > @@ -65,13 +65,13 @@ int dump_udp6(struct bpf_iter__udp *ctx)
> >  		       dest->s6_addr32[0], dest->s6_addr32[1],
> >  		       dest->s6_addr32[2], dest->s6_addr32[3], destp);
> >  
> > -	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u\n",
> > +	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %8d %u\n",
> 
> [Severity: Low]
> Is the use of %8d here in dump_udp6() introducing the same formatting
> mismatch as in dump_udp4()?
> 
> It seems it should use a literal 0 instead of %8d to exactly match the
> networking subsystem's native output format.

Yes it does but the extra spacing intends to align with the columns…

Sebastian

Re: [PATCH bpf-next] selftests/bpf: Replace %pK output with 0

[bot+bpf-ci]

[-- Attachment #1: Type: text/plain, Size: 4064 bytes --]

> diff --git a/tools/testing/selftests/bpf/README.rst b/tools/testing/selftests/bpf/README.rst
> index 07c834433b38..75ff1142c185 100644
> --- a/tools/testing/selftests/bpf/README.rst
> +++ b/tools/testing/selftests/bpf/README.rst
> @@ -187,7 +187,7 @@ The symptom for ``bpf_iter/netlink`` looks like
>    ...
>    15: (bf) r2 = r7
>    16: (0f) r2 += r1
> -  ; BPF_SEQ_PRINTF(seq, "%pK %-3d ", s, s->sk_protocol);
> +  ; BPF_SEQ_PRINTF(seq, "%p %-3d ", s, s->sk_protocol);
>    17: (7b) *(u64 *)(r7 +0) = r2
>    only read is supported

This excerpt is a historical clang-10 verifier log illustrating an old
failure case. The patch rewrites the quoted source to "%p %-3d ", but the
actual code now reads BPF_SEQ_PRINTF(seq, "0  %-3d ", s->sk_protocol) in
bpf_iter_netlink.c - the sock pointer argument is gone entirely.

Should the historical log remain untouched, or should it be updated to
reflect that the netlink iterator no longer passes a pointer to
BPF_SEQ_PRINTF?

> diff --git a/tools/testing/selftests/bpf/prog_tests/snprintf.c b/tools/testing/selftests/bpf/prog_tests/snprintf.c
> index 4e4a82d54f79..f2cd442c4683 100644
> --- a/tools/testing/selftests/bpf/prog_tests/snprintf.c
> +++ b/tools/testing/selftests/bpf/prog_tests/snprintf.c
> @@ -16,7 +16,7 @@
>  #define MIN_SYM_RET  sizeof(EXP_SYM_OUT)
>
>  /* The third specifier, %p, is a hashed pointer which changes on every reboot */
> -#define EXP_ADDR_OUT "0000000000000000 ffff00000add4e55 "
> +#define EXP_ADDR_OUT "ffff00000add4e55 "
>  #define EXP_ADDR_RET sizeof(EXP_ADDR_OUT "unknownhashedptr")

The comment says %p is the third specifier, but after removing %pK from
the BPF program (test_snprintf.c:59), %p is now the second specifier in
the format string "%px %p".

Should this comment be updated to say "The second specifier"?

[ ... ]

> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_unix.c b/tools/testing/selftests/bpf/progs/bpf_iter_unix.c
> index a2652c8c3616..36690478992f 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_unix.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_unix.c
> @@ -44,8 +44,7 @@ int dump_unix(struct bpf_iter__unix *ctx)
>  	if (seq_num == 0)
>  		BPF_SEQ_PRINTF(seq, "Num               RefCount Protocol Flags    Type St    Inode Path\n");
>
> -	BPF_SEQ_PRINTF(seq, "%pK: %08X %08X %08X %04X %02X %8lu",
> -		       unix_sk,
> +	BPF_SEQ_PRINTF(seq, "%08u: %08X %08X %08X %04X %02X %8lu", 0,
>  		       sk->sk_refcnt.refs.counter,
>  		       0,
>  		       sk->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,

The header shows "Num               RefCount" (18 columns before RefCount).
The old format "%pK: " produced 18 columns (16 hex digits + ':' + ' '),
matching the header width.

The new format "%08u: " with argument 0 produces "00000000: " (10 columns),
so every column from RefCount onward is now shifted 8 characters left of
its header label.

Should the header be updated to match the new field width, similar to how
bpf_iter_netlink.c was adjusted from "sk               Eth" to "sk Eth"?

Regarding the commit message:

> Networking recently replaced the socket output with a plain 0 because the
> socket pointer added no value to the output and the %pK should be removed
> fom library handling. The format remained otherwise unchanged in order not
> to break any tools which are parsing this information.

There's a typo: "fom library handling" should be "from library handling".

Also, the statement "The format remained otherwise unchanged" is
contradicted by the netlink header change from "sk               Eth Pid"
to "sk Eth Pid", and by the field width changes across all modified files
(varying from 1 to 10 columns vs the original 16-17 columns).

If maintaining format stability for parsers is the stated goal, should the
width-preserving spelling be used consistently?


---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md

CI run summary: https://github.com/kernel-patches/bpf/actions/runs/34614571384

Re: [PATCH bpf-next] selftests/bpf: Replace %pK output with 0

[Sebastian Andrzej Siewior]

On 2026-09-11 15:41:45 [+0000], bot+bpf-ci@kernel.org wrote:
> > diff --git a/tools/testing/selftests/bpf/README.rst b/tools/testing/selftests/bpf/README.rst
> > index 07c834433b38..75ff1142c185 100644
> > --- a/tools/testing/selftests/bpf/README.rst
> > +++ b/tools/testing/selftests/bpf/README.rst
> > @@ -187,7 +187,7 @@ The symptom for ``bpf_iter/netlink`` looks like
> >    ...
> >    15: (bf) r2 = r7
> >    16: (0f) r2 += r1
> > -  ; BPF_SEQ_PRINTF(seq, "%pK %-3d ", s, s->sk_protocol);
> > +  ; BPF_SEQ_PRINTF(seq, "%p %-3d ", s, s->sk_protocol);
> >    17: (7b) *(u64 *)(r7 +0) = r2
> >    only read is supported
> 
> This excerpt is a historical clang-10 verifier log illustrating an old
> failure case. The patch rewrites the quoted source to "%p %-3d ", but the
> actual code now reads BPF_SEQ_PRINTF(seq, "0  %-3d ", s->sk_protocol) in
> bpf_iter_netlink.c - the sock pointer argument is gone entirely.
> 
> Should the historical log remain untouched, or should it be updated to
> reflect that the netlink iterator no longer passes a pointer to
> BPF_SEQ_PRINTF?

I would prefer to remove the K and the plain %p should provide the same
historical input. Replacing it with 0 (and removing the argument) might
no longer do the job. As of commit ce3267a39a92b ("kbuild: Bump minimum
version of LLVM for building the kernel to 17.0.1") the minimum required
version is way passed 10. I don't know if this also applies to BPF here
(but why not?). If the required version is 17+, then there is probably
no need to reference a fix for llvm which is included as 11+.

> > diff --git a/tools/testing/selftests/bpf/prog_tests/snprintf.c b/tools/testing/selftests/bpf/prog_tests/snprintf.c
> > index 4e4a82d54f79..f2cd442c4683 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/snprintf.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/snprintf.c
> > @@ -16,7 +16,7 @@
> >  #define MIN_SYM_RET  sizeof(EXP_SYM_OUT)
> >
> >  /* The third specifier, %p, is a hashed pointer which changes on every reboot */
> > -#define EXP_ADDR_OUT "0000000000000000 ffff00000add4e55 "
> > +#define EXP_ADDR_OUT "ffff00000add4e55 "
> >  #define EXP_ADDR_RET sizeof(EXP_ADDR_OUT "unknownhashedptr")
> 
> The comment says %p is the third specifier, but after removing %pK from
> the BPF program (test_snprintf.c:59), %p is now the second specifier in
> the format string "%px %p".
> 
> Should this comment be updated to say "The second specifier"?

Yeah, that makes sense.

> [ ... ]
> 
> > diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_unix.c b/tools/testing/selftests/bpf/progs/bpf_iter_unix.c
> > index a2652c8c3616..36690478992f 100644
> > --- a/tools/testing/selftests/bpf/progs/bpf_iter_unix.c
> > +++ b/tools/testing/selftests/bpf/progs/bpf_iter_unix.c
> > @@ -44,8 +44,7 @@ int dump_unix(struct bpf_iter__unix *ctx)
> >  	if (seq_num == 0)
> >  		BPF_SEQ_PRINTF(seq, "Num               RefCount Protocol Flags    Type St    Inode Path\n");
> >
> > -	BPF_SEQ_PRINTF(seq, "%pK: %08X %08X %08X %04X %02X %8lu",
> > -		       unix_sk,
> > +	BPF_SEQ_PRINTF(seq, "%08u: %08X %08X %08X %04X %02X %8lu", 0,
> >  		       sk->sk_refcnt.refs.counter,
> >  		       0,
> >  		       sk->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
> 
> The header shows "Num               RefCount" (18 columns before RefCount).
> The old format "%pK: " produced 18 columns (16 hex digits + ':' + ' '),
> matching the header width.
> 
> The new format "%08u: " with argument 0 produces "00000000: " (10 columns),
> so every column from RefCount onward is now shifted 8 characters left of
> its header label.
> 
> Should the header be updated to match the new field width, similar to how
> bpf_iter_netlink.c was adjusted from "sk               Eth" to "sk Eth"?

Missed that. The net: version expected a 32bit pointer while the bpf one
expects always a 64bit pointer. I tried to shrink the net one to
something smaller but there was a selftest somewhere expecting the exact
size so I just went with it.

Let me align everything with net then shrink this one including the
description, too.

> Regarding the commit message:
> 
> > Networking recently replaced the socket output with a plain 0 because the
> > socket pointer added no value to the output and the %pK should be removed
> > fom library handling. The format remained otherwise unchanged in order not
> > to break any tools which are parsing this information.
> 
> There's a typo: "fom library handling" should be "from library handling".

Thank you.

> Also, the statement "The format remained otherwise unchanged" is
> contradicted by the netlink header change from "sk               Eth Pid"
> to "sk Eth Pid", and by the field width changes across all modified files
> (varying from 1 to 10 columns vs the original 16-17 columns).
> 
> If maintaining format stability for parsers is the stated goal, should the
> width-preserving spelling be used consistently?

"stability for parsers" means not to remove pointer and therefore a
column so it will work for the human eye but the parse would expect a
certain column. The padding here is just for the human eye and the
parser does not care.

Sebastian

Re: [PATCH bpf-next] selftests/bpf: Replace %pK output with 0

[Emil Tsalapatis]

On Fri Sep 11, 2026 at 2:50 PM UTC, Sebastian Andrzej Siewior wrote:
> Networking used to print the socket pointer with %p as output in the
> /proc interface. This was later changed to %pK in order not to reveal
> the actual pointer value. The output format has then been copied to bpf
> tests which produce the same format including the %pK format modifier.
>
> Networking recently replaced the socket output with a plain 0 because
> the socket pointer added no value to the output and the %pK should be
> removed fom library handling. The format remained otherwise unchanged in
> order not to break any tools which are parsing this information.
>
> This change removes the %pK modifier from bpf, following the change in
> networking.
>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>

The bots are being overly picky bere, the tests pass fine and these are
selftests anyway.

> ---
>
> The networking change is in net-next as commit 7c0ec6288b497 ("net:
> Replace %pK output with 0")
>
>  tools/testing/selftests/bpf/README.rst               |  2 +-
>  tools/testing/selftests/bpf/prog_tests/snprintf.c    |  2 +-
>  tools/testing/selftests/bpf/progs/bpf_iter_netlink.c |  4 ++--
>  tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c    | 11 +++++------
>  tools/testing/selftests/bpf/progs/bpf_iter_tcp6.c    | 11 +++++------
>  tools/testing/selftests/bpf/progs/bpf_iter_udp4.c    |  4 ++--
>  tools/testing/selftests/bpf/progs/bpf_iter_udp6.c    |  4 ++--
>  tools/testing/selftests/bpf/progs/bpf_iter_unix.c    |  3 +--
>  tools/testing/selftests/bpf/progs/test_snprintf.c    |  4 ++--
>  9 files changed, 21 insertions(+), 24 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/README.rst b/tools/testing/selftests/bpf/README.rst
> index 07c834433b388..75ff1142c1857 100644
> --- a/tools/testing/selftests/bpf/README.rst
> +++ b/tools/testing/selftests/bpf/README.rst
> @@ -187,7 +187,7 @@ The symptom for ``bpf_iter/netlink`` looks like
>    ...
>    15: (bf) r2 = r7
>    16: (0f) r2 += r1
> -  ; BPF_SEQ_PRINTF(seq, "%pK %-3d ", s, s->sk_protocol);
> +  ; BPF_SEQ_PRINTF(seq, "%p %-3d ", s, s->sk_protocol);
>    17: (7b) *(u64 *)(r7 +0) = r2
>    only read is supported
>  
> diff --git a/tools/testing/selftests/bpf/prog_tests/snprintf.c b/tools/testing/selftests/bpf/prog_tests/snprintf.c
> index 4e4a82d54f799..f2cd442c4683c 100644
> --- a/tools/testing/selftests/bpf/prog_tests/snprintf.c
> +++ b/tools/testing/selftests/bpf/prog_tests/snprintf.c
> @@ -16,7 +16,7 @@
>  #define MIN_SYM_RET  sizeof(EXP_SYM_OUT)
>  
>  /* The third specifier, %p, is a hashed pointer which changes on every reboot */
> -#define EXP_ADDR_OUT "0000000000000000 ffff00000add4e55 "
> +#define EXP_ADDR_OUT "ffff00000add4e55 "
>  #define EXP_ADDR_RET sizeof(EXP_ADDR_OUT "unknownhashedptr")
>  
>  #define EXP_STR_OUT  "str1         a  b c      d e longstr"
> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_netlink.c b/tools/testing/selftests/bpf/progs/bpf_iter_netlink.c
> index 00b2ceae81fb0..b9107d3ab6039 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_netlink.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_netlink.c
> @@ -25,12 +25,12 @@ int dump_netlink(struct bpf_iter__netlink *ctx)
>  		return 0;
>  
>  	if (ctx->meta->seq_num == 0)
> -		BPF_SEQ_PRINTF(seq, "sk               Eth Pid        Groups   "
> +		BPF_SEQ_PRINTF(seq, "sk Eth Pid        Groups   "
>  				    "Rmem     Wmem     Dump  Locks    Drops    "
>  				    "Inode\n");
>  
>  	s = &nlk->sk;
> -	BPF_SEQ_PRINTF(seq, "%pK %-3d ", s, s->sk_protocol);
> +	BPF_SEQ_PRINTF(seq, "0  %-3d ", s->sk_protocol);
>  
>  	if (!nlk->groups)  {
>  		group = 0;
> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c b/tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c
> index b1e509b231cd9..d149cf0d07be6 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c
> @@ -131,8 +131,7 @@ static int dump_tcp_sock(struct seq_file *seq, struct tcp_sock *tp,
>  		       icsk->icsk_probes_out,
>  		       sock_i_ino(sp),
>  		       sp->sk_refcnt.refs.counter);
> -	BPF_SEQ_PRINTF(seq, "%pK %lu %lu %u %u %d\n",
> -		       tp,
> +	BPF_SEQ_PRINTF(seq, "0 %lu %lu %u %u %d\n",
>  		       jiffies_to_clock_t(icsk->icsk_rto),
>  		       jiffies_to_clock_t(icsk->icsk_ack.ato),
>  		       (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(icsk),
> @@ -161,10 +160,10 @@ static int dump_tw_sock(struct seq_file *seq, struct tcp_timewait_sock *ttw,
>  	BPF_SEQ_PRINTF(seq, "%4d: %08X:%04X %08X:%04X ",
>  		       seq_num, src, srcp, dest, destp);
>  
> -	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
> +	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d 0\n",
>  		       tw->tw_substate, 0, 0,
>  		       3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
> -		       tw->tw_refcnt.refs.counter, tw);
> +		       tw->tw_refcnt.refs.counter);
>  
>  	return 0;
>  }
> @@ -185,9 +184,9 @@ static int dump_req_sock(struct seq_file *seq, struct tcp_request_sock *treq,
>  		       seq_num, irsk->ir_loc_addr,
>  		       irsk->ir_num, irsk->ir_rmt_addr,
>  		       bpf_ntohs(irsk->ir_rmt_port));
> -	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
> +	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d 0\n",
>  		       TCP_SYN_RECV, 0, 0, 1, jiffies_to_clock_t(ttd),
> -		       req->num_timeout, uid, 0, 0, 0, req);
> +		       req->num_timeout, uid, 0, 0, 0);
>  
>  	return 0;
>  }
> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_tcp6.c b/tools/testing/selftests/bpf/progs/bpf_iter_tcp6.c
> index dbc7166aee91f..cd65fa81f1219 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_tcp6.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_tcp6.c
> @@ -135,8 +135,7 @@ static int dump_tcp6_sock(struct seq_file *seq, struct tcp6_sock *tp,
>  		       icsk->icsk_probes_out,
>  		       sock_i_ino(sp),
>  		       sp->sk_refcnt.refs.counter);
> -	BPF_SEQ_PRINTF(seq, "%pK %lu %lu %u %u %d\n",
> -		       tp,
> +	BPF_SEQ_PRINTF(seq, "0 %lu %lu %u %u %d\n",
>  		       jiffies_to_clock_t(icsk->icsk_rto),
>  		       jiffies_to_clock_t(icsk->icsk_ack.ato),
>  		       (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(icsk),
> @@ -170,10 +169,10 @@ static int dump_tw_sock(struct seq_file *seq, struct tcp_timewait_sock *ttw,
>  		       dest->s6_addr32[0], dest->s6_addr32[1],
>  		       dest->s6_addr32[2], dest->s6_addr32[3], destp);
>  
> -	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
> +	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d 0\n",
>  		       tw->tw_substate, 0, 0,
>  		       3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
> -		       tw->tw_refcnt.refs.counter, tw);
> +		       tw->tw_refcnt.refs.counter);
>  
>  	return 0;
>  }
> @@ -201,9 +200,9 @@ static int dump_req_sock(struct seq_file *seq, struct tcp_request_sock *treq,
>  		       dest->s6_addr32[0], dest->s6_addr32[1],
>  		       dest->s6_addr32[2], dest->s6_addr32[3],
>  		       bpf_ntohs(irsk->ir_rmt_port));
> -	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
> +	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d 0\n",
>  		       TCP_SYN_RECV, 0, 0, 1, jiffies_to_clock_t(ttd),
> -		       req->num_timeout, uid, 0, 0, 0, req);
> +		       req->num_timeout, uid, 0, 0, 0);
>  
>  	return 0;
>  }
> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_udp4.c b/tools/testing/selftests/bpf/progs/bpf_iter_udp4.c
> index 23b2aa2604de2..9b789f09f1462 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_udp4.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_udp4.c
> @@ -57,13 +57,13 @@ int dump_udp4(struct bpf_iter__udp *ctx)
>  	BPF_SEQ_PRINTF(seq, "%5d: %08X:%04X %08X:%04X ",
>  		       ctx->bucket, src, srcp, dest, destp);
>  
> -	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u\n",
> +	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %8d %u\n",
>  		       inet->sk.sk_state,
>  		       inet->sk.sk_wmem_alloc.refs.counter - 1,
>  		       rqueue,
>  		       0, 0L, 0, ctx->uid, 0,
>  		       sock_i_ino(&inet->sk),
> -		       inet->sk.sk_refcnt.refs.counter, udp_sk,
> +		       inet->sk.sk_refcnt.refs.counter, 0,
>  		       udp_sk->drop_counters.drops0.counter +
>  		       udp_sk->drop_counters.drops1.counter);
>  
> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_udp6.c b/tools/testing/selftests/bpf/progs/bpf_iter_udp6.c
> index c48b05aa2a4b2..9766eff7069ff 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_udp6.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_udp6.c
> @@ -65,13 +65,13 @@ int dump_udp6(struct bpf_iter__udp *ctx)
>  		       dest->s6_addr32[0], dest->s6_addr32[1],
>  		       dest->s6_addr32[2], dest->s6_addr32[3], destp);
>  
> -	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u\n",
> +	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %8d %u\n",
>  		       inet->sk.sk_state,
>  		       inet->sk.sk_wmem_alloc.refs.counter - 1,
>  		       rqueue,
>  		       0, 0L, 0, ctx->uid, 0,
>  		       sock_i_ino(&inet->sk),
> -		       inet->sk.sk_refcnt.refs.counter, udp_sk,
> +		       inet->sk.sk_refcnt.refs.counter, 0,
>  		       udp_sk->drop_counters.drops0.counter +
>  		       udp_sk->drop_counters.drops1.counter);
>  	return 0;
> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_unix.c b/tools/testing/selftests/bpf/progs/bpf_iter_unix.c
> index a2652c8c3616f..36690478992f8 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_unix.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_unix.c
> @@ -44,8 +44,7 @@ int dump_unix(struct bpf_iter__unix *ctx)
>  	if (seq_num == 0)
>  		BPF_SEQ_PRINTF(seq, "Num               RefCount Protocol Flags    Type St    Inode Path\n");
>  
> -	BPF_SEQ_PRINTF(seq, "%pK: %08X %08X %08X %04X %02X %8lu",
> -		       unix_sk,
> +	BPF_SEQ_PRINTF(seq, "%08u: %08X %08X %08X %04X %02X %8lu", 0,
>  		       sk->sk_refcnt.refs.counter,
>  		       0,
>  		       sk->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
> diff --git a/tools/testing/selftests/bpf/progs/test_snprintf.c b/tools/testing/selftests/bpf/progs/test_snprintf.c
> index 8fda075440235..48a0025cf2ca8 100644
> --- a/tools/testing/selftests/bpf/progs/test_snprintf.c
> +++ b/tools/testing/selftests/bpf/progs/test_snprintf.c
> @@ -57,8 +57,8 @@ int handler(const void *ctx)
>  	sym_ret  = BPF_SNPRINTF(sym_out,  sizeof(sym_out), "%ps %pS %pB",
>  				&schedule, &schedule, &schedule);
>  	/* Kernel pointers */
> -	addr_ret = BPF_SNPRINTF(addr_out, sizeof(addr_out), "%pK %px %p",
> -				0, 0xFFFF00000ADD4E55, 0xFFFF00000ADD4E55);
> +	addr_ret = BPF_SNPRINTF(addr_out, sizeof(addr_out), "%px %p",
> +				0xFFFF00000ADD4E55, 0xFFFF00000ADD4E55);
>  	/* Strings and single-byte character embedding */
>  	str_ret  = BPF_SNPRINTF(str_out, sizeof(str_out), "%s % 9c %+2c %-3c %04c %0c %+05s",
>  				str1, 'a', 'b', 'c', 'd', 'e', longstr);

Re: [PATCH bpf-next] selftests/bpf: Replace %pK output with 0

[Sebastian Andrzej Siewior]

On 2026-09-14 23:39:22 [+0000], Emil Tsalapatis wrote:
> On Fri Sep 11, 2026 at 2:50 PM UTC, Sebastian Andrzej Siewior wrote:
> > Networking used to print the socket pointer with %p as output in the
> > /proc interface. This was later changed to %pK in order not to reveal
> > the actual pointer value. The output format has then been copied to bpf
> > tests which produce the same format including the %pK format modifier.
> >
> > Networking recently replaced the socket output with a plain 0 because
> > the socket pointer added no value to the output and the %pK should be
> > removed fom library handling. The format remained otherwise unchanged in
> > order not to break any tools which are parsing this information.
> >
> > This change removes the %pK modifier from bpf, following the change in
> > networking.
> >
> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> 
> Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
> 
> The bots are being overly picky bere, the tests pass fine and these are
> selftests anyway.

I would repost it with comment updated. I am just unsure about
README.rst part. Should that pointer about llvm 10 be removed (because
outdated) or kept as I have it? 

Sebastian