[PATCH AUTOSEL 4.19 34/84] bpf, mips: Limit to 33 tail calls

[PATCH AUTOSEL 4.19 34/84] bpf, mips: Limit to 33 tail calls

[Sasha Levin]

From: Paul Chaignon <paul.chaignon@orange.com>

[ Upstream commit e49e6f6db04e915dccb494ae10fa14888fea6f89 ]

All BPF JIT compilers except RISC-V's and MIPS' enforce a 33-tail calls
limit at runtime.  In addition, a test was recently added, in tailcalls2,
to check this limit.

This patch updates the tail call limit in MIPS' JIT compiler to allow
33 tail calls.

Fixes: b6bd53f9c4e8 ("MIPS: Add missing file for eBPF JIT.")
Reported-by: Mahshid Khezri <khezri.mahshid@gmail.com>
Signed-off-by: Paul Chaignon <paul.chaignon@orange.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/b8eb2caac1c25453c539248e56ca22f74b5316af.1575916815.git.paul.chaignon@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/mips/net/ebpf_jit.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/mips/net/ebpf_jit.c b/arch/mips/net/ebpf_jit.c
index 9bda82ed75eb..3832c4628608 100644
--- a/arch/mips/net/ebpf_jit.c
+++ b/arch/mips/net/ebpf_jit.c
@@ -586,6 +586,7 @@ static void emit_const_to_reg(struct jit_ctx *ctx, int dst, u64 value)
 static int emit_bpf_tail_call(struct jit_ctx *ctx, int this_idx)
 {
 	int off, b_off;
+	int tcc_reg;
 
 	ctx->flags |= EBPF_SEEN_TC;
 	/*
@@ -598,14 +599,14 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx, int this_idx)
 	b_off = b_imm(this_idx + 1, ctx);
 	emit_instr(ctx, bne, MIPS_R_AT, MIPS_R_ZERO, b_off);
 	/*
-	 * if (--TCC < 0)
+	 * if (TCC-- < 0)
 	 *     goto out;
 	 */
 	/* Delay slot */
-	emit_instr(ctx, daddiu, MIPS_R_T5,
-		   (ctx->flags & EBPF_TCC_IN_V1) ? MIPS_R_V1 : MIPS_R_S4, -1);
+	tcc_reg = (ctx->flags & EBPF_TCC_IN_V1) ? MIPS_R_V1 : MIPS_R_S4;
+	emit_instr(ctx, daddiu, MIPS_R_T5, tcc_reg, -1);
 	b_off = b_imm(this_idx + 1, ctx);
-	emit_instr(ctx, bltz, MIPS_R_T5, b_off);
+	emit_instr(ctx, bltz, tcc_reg, b_off);
 	/*
 	 * prog = array->ptrs[index];
 	 * if (prog == NULL)
-- 
2.20.1

[PATCH AUTOSEL 4.19 37/84] samples: bpf: Replace symbol compare of trace_event

[Sasha Levin]

From: "Daniel T. Lee" <danieltimlee@gmail.com>

[ Upstream commit bba1b2a890253528c45aa66cf856f289a215bfbc ]

Previously, when this sample is added, commit 1c47910ef8013
("samples/bpf: add perf_event+bpf example"), a symbol 'sys_read' and
'sys_write' has been used without no prefixes. But currently there are
no exact symbols with these under kallsyms and this leads to failure.

This commit changes exact compare to substring compare to keep compatible
with exact symbol or prefixed symbol.

Fixes: 1c47910ef8013 ("samples/bpf: add perf_event+bpf example")
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191205080114.19766-2-danieltimlee@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 samples/bpf/trace_event_user.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/samples/bpf/trace_event_user.c b/samples/bpf/trace_event_user.c
index d08046ab81f0..d33022447d6b 100644
--- a/samples/bpf/trace_event_user.c
+++ b/samples/bpf/trace_event_user.c
@@ -35,9 +35,9 @@ static void print_ksym(__u64 addr)
 		return;
 	sym = ksym_search(addr);
 	printf("%s;", sym->name);
-	if (!strcmp(sym->name, "sys_read"))
+	if (!strstr(sym->name, "sys_read"))
 		sys_read_seen = true;
-	else if (!strcmp(sym->name, "sys_write"))
+	else if (!strstr(sym->name, "sys_write"))
 		sys_write_seen = true;
 }
 
-- 
2.20.1

[PATCH AUTOSEL 4.19 38/84] samples: bpf: fix syscall_tp due to unused syscall

[Sasha Levin]

From: "Daniel T. Lee" <danieltimlee@gmail.com>

[ Upstream commit fe3300897cbfd76c6cb825776e5ac0ca50a91ca4 ]

Currently, open() is called from the user program and it calls the syscall
'sys_openat', not the 'sys_open'. This leads to an error of the program
of user side, due to the fact that the counter maps are zero since no
function such 'sys_open' is called.

This commit adds the kernel bpf program which are attached to the
tracepoint 'sys_enter_openat' and 'sys_enter_openat'.

Fixes: 1da236b6be963 ("bpf: add a test case for syscalls/sys_{enter|exit}_* tracepoints")
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 samples/bpf/syscall_tp_kern.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/samples/bpf/syscall_tp_kern.c b/samples/bpf/syscall_tp_kern.c
index 9149c524d279..8833aacb9c8c 100644
--- a/samples/bpf/syscall_tp_kern.c
+++ b/samples/bpf/syscall_tp_kern.c
@@ -50,13 +50,27 @@ static __always_inline void count(void *map)
 SEC("tracepoint/syscalls/sys_enter_open")
 int trace_enter_open(struct syscalls_enter_open_args *ctx)
 {
-	count((void *)&enter_open_map);
+	count(&enter_open_map);
+	return 0;
+}
+
+SEC("tracepoint/syscalls/sys_enter_openat")
+int trace_enter_open_at(struct syscalls_enter_open_args *ctx)
+{
+	count(&enter_open_map);
 	return 0;
 }
 
 SEC("tracepoint/syscalls/sys_exit_open")
 int trace_enter_exit(struct syscalls_exit_open_args *ctx)
 {
-	count((void *)&exit_open_map);
+	count(&exit_open_map);
+	return 0;
+}
+
+SEC("tracepoint/syscalls/sys_exit_openat")
+int trace_enter_exit_at(struct syscalls_exit_open_args *ctx)
+{
+	count(&exit_open_map);
 	return 0;
 }
-- 
2.20.1

[PATCH AUTOSEL 4.19 45/84] bpf: Clear skb->tstamp in bpf_redirect when necessary

[Sasha Levin]

From: Lorenz Bauer <lmb@cloudflare.com>

[ Upstream commit 5133498f4ad1123a5ffd4c08df6431dab882cc32 ]

Redirecting a packet from ingress to egress by using bpf_redirect
breaks if the egress interface has an fq qdisc installed. This is the same
problem as fixed in 'commit 8203e2d844d3 ("net: clear skb->tstamp in forwarding paths")

Clear skb->tstamp when redirecting into the egress path.

Fixes: 80b14dee2bea ("net: Add a new socket option for a future transmit time.")
Fixes: fb420d5d91c1 ("tcp/fq: move back to CLOCK_MONOTONIC")
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/bpf/20191213180817.2510-1-lmb@cloudflare.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/core/filter.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/core/filter.c b/net/core/filter.c
index e6fa88506c00..91b950261975 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2007,6 +2007,7 @@ static inline int __bpf_tx_skb(struct net_device *dev, struct sk_buff *skb)
 	}
 
 	skb->dev = dev;
+	skb->tstamp = 0;
 
 	__this_cpu_inc(xmit_recursion);
 	ret = dev_queue_xmit(skb);
-- 
2.20.1

[PATCH AUTOSEL 4.19 75/84] net, sysctl: Fix compiler warning when only cBPF is present

[Sasha Levin]

From: Alexander Lobakin <alobakin@dlink.ru>

[ Upstream commit 1148f9adbe71415836a18a36c1b4ece999ab0973 ]

proc_dointvec_minmax_bpf_restricted() has been firstly introduced
in commit 2e4a30983b0f ("bpf: restrict access to core bpf sysctls")
under CONFIG_HAVE_EBPF_JIT. Then, this ifdef has been removed in
ede95a63b5e8 ("bpf: add bpf_jit_limit knob to restrict unpriv
allocations"), because a new sysctl, bpf_jit_limit, made use of it.
Finally, this parameter has become long instead of integer with
fdadd04931c2 ("bpf: fix bpf_jit_limit knob for PAGE_SIZE >= 64K")
and thus, a new proc_dolongvec_minmax_bpf_restricted() has been
added.

With this last change, we got back to that
proc_dointvec_minmax_bpf_restricted() is used only under
CONFIG_HAVE_EBPF_JIT, but the corresponding ifdef has not been
brought back.

So, in configurations like CONFIG_BPF_JIT=y && CONFIG_HAVE_EBPF_JIT=n
since v4.20 we have:

  CC      net/core/sysctl_net_core.o
net/core/sysctl_net_core.c:292:1: warning: ‘proc_dointvec_minmax_bpf_restricted’ defined but not used [-Wunused-function]
  292 | proc_dointvec_minmax_bpf_restricted(struct ctl_table *table, int write,
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Suppress this by guarding it with CONFIG_HAVE_EBPF_JIT again.

Fixes: fdadd04931c2 ("bpf: fix bpf_jit_limit knob for PAGE_SIZE >= 64K")
Signed-off-by: Alexander Lobakin <alobakin@dlink.ru>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191218091821.7080-1-alobakin@dlink.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/core/sysctl_net_core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index d67ec17f2cc8..6cec08cd0bb9 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -281,6 +281,7 @@ static int proc_dointvec_minmax_bpf_enable(struct ctl_table *table, int write,
 	return ret;
 }
 
+# ifdef CONFIG_HAVE_EBPF_JIT
 static int
 proc_dointvec_minmax_bpf_restricted(struct ctl_table *table, int write,
 				    void __user *buffer, size_t *lenp,
@@ -291,6 +292,7 @@ proc_dointvec_minmax_bpf_restricted(struct ctl_table *table, int write,
 
 	return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
 }
+# endif /* CONFIG_HAVE_EBPF_JIT */
 
 static int
 proc_dolongvec_minmax_bpf_restricted(struct ctl_table *table, int write,
-- 
2.20.1