[PATCH AUTOSEL 5.4 071/187] bpf, riscv: Limit to 33 tail calls

[PATCH AUTOSEL 5.4 071/187] bpf, riscv: Limit to 33 tail calls

[Sasha Levin]

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

[ Upstream commit 96bc4432f5ade1045521f3b247f516b1478166bd ]

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 RISC-V's JIT compiler to allow
33 tail calls.  I tested it using the above selftest on an emulated
RISCV64.

Fixes: 2353ecc6f91f ("bpf, riscv: add BPF JIT for RV64G")
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: Björn Töpel <bjorn.topel@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/966fe384383bf23a0ee1efe8d7291c78a3fb832b.1575916815.git.paul.chaignon@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/riscv/net/bpf_jit_comp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/net/bpf_jit_comp.c b/arch/riscv/net/bpf_jit_comp.c
index 5451ef3845f2..7fbf56aab661 100644
--- a/arch/riscv/net/bpf_jit_comp.c
+++ b/arch/riscv/net/bpf_jit_comp.c
@@ -631,14 +631,14 @@ static int emit_bpf_tail_call(int insn, struct rv_jit_context *ctx)
 		return -1;
 	emit(rv_bgeu(RV_REG_A2, RV_REG_T1, off >> 1), ctx);
 
-	/* if (--TCC < 0)
+	/* if (TCC-- < 0)
 	 *     goto out;
 	 */
 	emit(rv_addi(RV_REG_T1, tcc, -1), ctx);
 	off = (tc_ninsn - (ctx->ninsns - start_insn)) << 2;
 	if (is_13b_check(off, insn))
 		return -1;
-	emit(rv_blt(RV_REG_T1, RV_REG_ZERO, off >> 1), ctx);
+	emit(rv_blt(tcc, RV_REG_ZERO, off >> 1), ctx);
 
 	/* prog = array->ptrs[index];
 	 * if (!prog)
-- 
2.20.1

[PATCH AUTOSEL 5.4 072/187] 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 46b76751f3a5..3ec69d9cbe88 100644
--- a/arch/mips/net/ebpf_jit.c
+++ b/arch/mips/net/ebpf_jit.c
@@ -604,6 +604,7 @@ 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;
 	/*
@@ -616,14 +617,14 @@ 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 5.4 073/187] bpftool: Don't crash on missing jited insns or ksyms

[Sasha Levin]

From: Toke Høiland-Jørgensen <toke@redhat.com>

[ Upstream commit 5b79bcdf03628a3a9ee04d9cd5fabcf61a8e20be ]

When the kptr_restrict sysctl is set, the kernel can fail to return
jited_ksyms or jited_prog_insns, but still have positive values in
nr_jited_ksyms and jited_prog_len. This causes bpftool to crash when
trying to dump the program because it only checks the len fields not
the actual pointers to the instructions and ksyms.

Fix this by adding the missing checks.

Fixes: 71bb428fe2c1 ("tools: bpf: add bpftool")
Fixes: f84192ee00b7 ("tools: bpftool: resolve calls without using imm field")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191210181412.151226-1-toke@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/bpf/bpftool/prog.c          | 2 +-
 tools/bpf/bpftool/xlated_dumper.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 43fdbbfe41bb..ea0bcd58bcb9 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -493,7 +493,7 @@ static int do_dump(int argc, char **argv)
 
 	info = &info_linear->info;
 	if (mode == DUMP_JITED) {
-		if (info->jited_prog_len == 0) {
+		if (info->jited_prog_len == 0 || !info->jited_prog_insns) {
 			p_info("no instructions returned");
 			goto err_free;
 		}
diff --git a/tools/bpf/bpftool/xlated_dumper.c b/tools/bpf/bpftool/xlated_dumper.c
index 494d7ae3614d..5b91ee65a080 100644
--- a/tools/bpf/bpftool/xlated_dumper.c
+++ b/tools/bpf/bpftool/xlated_dumper.c
@@ -174,7 +174,7 @@ static const char *print_call(void *private_data,
 	struct kernel_sym *sym;
 
 	if (insn->src_reg == BPF_PSEUDO_CALL &&
-	    (__u32) insn->imm < dd->nr_jited_ksyms)
+	    (__u32) insn->imm < dd->nr_jited_ksyms && dd->jited_ksyms)
 		address = dd->jited_ksyms[insn->imm];
 
 	sym = kernel_syms_search(dd, address);
-- 
2.20.1

[PATCH AUTOSEL 5.4 080/187] 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 16a16eadd509..749a50f2f9f3 100644
--- a/samples/bpf/trace_event_user.c
+++ b/samples/bpf/trace_event_user.c
@@ -37,9 +37,9 @@ static void print_ksym(__u64 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 5.4 081/187] 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 1d78819ffef1..630ce8c4d5a2 100644
--- a/samples/bpf/syscall_tp_kern.c
+++ b/samples/bpf/syscall_tp_kern.c
@@ -47,13 +47,27 @@ 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 5.4 100/187] 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 6d0111bfdb4a..2f76461c120d 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2055,6 +2055,7 @@ static inline int __bpf_tx_skb(struct net_device *dev, struct sk_buff *skb)
 	}
 
 	skb->dev = dev;
+	skb->tstamp = 0;
 
 	dev_xmit_recursion_inc();
 	ret = dev_queue_xmit(skb);
-- 
2.20.1