From f3edacbd697f94a743fff1a3d26910ab99948ba7 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Sat, 11 Nov 2017 18:24:55 +0900 Subject: [PATCH] bpf: Revert bpf_overrid_function() helper changes. NACK'd by x86 maintainer. Signed-off-by: David S. Miller --- arch/Kconfig | 3 --- arch/x86/Kconfig | 1 - arch/x86/include/asm/kprobes.h | 4 ---- arch/x86/include/asm/ptrace.h | 5 ---- arch/x86/kernel/kprobes/ftrace.c | 14 ----------- include/linux/filter.h | 3 +-- include/linux/trace_events.h | 1 - include/uapi/linux/bpf.h | 7 +----- kernel/bpf/core.c | 3 --- kernel/bpf/verifier.c | 2 -- kernel/events/core.c | 7 ------ kernel/trace/Kconfig | 11 --------- kernel/trace/bpf_trace.c | 35 --------------------------- kernel/trace/trace_kprobe.c | 40 ++++++------------------------- kernel/trace/trace_probe.h | 6 ----- samples/bpf/Makefile | 4 ---- samples/bpf/test_override_return.sh | 15 ------------ samples/bpf/tracex7_kern.c | 16 ------------- samples/bpf/tracex7_user.c | 28 ---------------------- tools/include/uapi/linux/bpf.h | 7 +----- tools/testing/selftests/bpf/bpf_helpers.h | 3 +-- 21 files changed, 11 insertions(+), 204 deletions(-) delete mode 100755 samples/bpf/test_override_return.sh delete mode 100644 samples/bpf/tracex7_kern.c delete mode 100644 samples/bpf/tracex7_user.c diff --git a/arch/Kconfig b/arch/Kconfig index 6e8520f09bc1..057370a0ac4e 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -196,9 +196,6 @@ config HAVE_OPTPROBES config HAVE_KPROBES_ON_FTRACE bool -config HAVE_KPROBE_OVERRIDE - bool - config HAVE_NMI bool diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 51458c1a0b4a..2fdb23313dd5 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -153,7 +153,6 @@ config X86 select HAVE_KERNEL_XZ select HAVE_KPROBES select HAVE_KPROBES_ON_FTRACE - select HAVE_KPROBE_OVERRIDE select HAVE_KRETPROBES select HAVE_KVM select HAVE_LIVEPATCH if X86_64 diff --git a/arch/x86/include/asm/kprobes.h b/arch/x86/include/asm/kprobes.h index c6c3b1f4306a..6cf65437b5e5 100644 --- a/arch/x86/include/asm/kprobes.h +++ b/arch/x86/include/asm/kprobes.h @@ -67,10 +67,6 @@ extern const int kretprobe_blacklist_size; void arch_remove_kprobe(struct kprobe *p); asmlinkage void kretprobe_trampoline(void); -#ifdef CONFIG_KPROBES_ON_FTRACE -extern void arch_ftrace_kprobe_override_function(struct pt_regs *regs); -#endif - /* Architecture specific copy of original instruction*/ struct arch_specific_insn { /* copy of the original instruction */ diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h index 2370bb0149cc..c0e3c45cf6ab 100644 --- a/arch/x86/include/asm/ptrace.h +++ b/arch/x86/include/asm/ptrace.h @@ -109,11 +109,6 @@ static inline unsigned long regs_return_value(struct pt_regs *regs) return regs->ax; } -static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc) -{ - regs->ax = rc; -} - /* * user_mode(regs) determines whether a register set came from user * mode. On x86_32, this is true if V8086 mode was enabled OR if the diff --git a/arch/x86/kernel/kprobes/ftrace.c b/arch/x86/kernel/kprobes/ftrace.c index 3c455bf490cb..041f7b6dfa0f 100644 --- a/arch/x86/kernel/kprobes/ftrace.c +++ b/arch/x86/kernel/kprobes/ftrace.c @@ -97,17 +97,3 @@ int arch_prepare_kprobe_ftrace(struct kprobe *p) p->ainsn.boostable = false; return 0; } - -asmlinkage void override_func(void); -asm( - ".type override_func, @function\n" - "override_func:\n" - " ret\n" - ".size override_func, .-override_func\n" -); - -void arch_ftrace_kprobe_override_function(struct pt_regs *regs) -{ - regs->ip = (unsigned long)&override_func; -} -NOKPROBE_SYMBOL(arch_ftrace_kprobe_override_function); diff --git a/include/linux/filter.h b/include/linux/filter.h index eaec066f99e8..0cd02ff4ae30 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -459,8 +459,7 @@ struct bpf_prog { locked:1, /* Program image locked? */ gpl_compatible:1, /* Is filter GPL compatible? */ cb_access:1, /* Is control block accessed? */ - dst_needed:1, /* Do we need dst entry? */ - kprobe_override:1; /* Do we override a kprobe? */ + dst_needed:1; /* Do we need dst entry? */ kmemcheck_bitfield_end(meta); enum bpf_prog_type type; /* Type of BPF program */ u32 len; /* Number of filter blocks */ diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index 17e5e820a84c..84014ecfa67f 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -523,7 +523,6 @@ do { \ struct perf_event; DECLARE_PER_CPU(struct pt_regs, perf_trace_regs); -DECLARE_PER_CPU(int, bpf_kprobe_override); extern int perf_trace_init(struct perf_event *event); extern void perf_trace_destroy(struct perf_event *event); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index adb66f78b674..e880ae6434ee 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -677,10 +677,6 @@ union bpf_attr { * @buf: buf to fill * @buf_size: size of the buf * Return : 0 on success or negative error code - * - * int bpf_override_return(pt_regs, rc) - * @pt_regs: pointer to struct pt_regs - * @rc: the return value to set */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -740,8 +736,7 @@ union bpf_attr { FN(xdp_adjust_meta), \ FN(perf_event_read_value), \ FN(perf_prog_read_value), \ - FN(getsockopt), \ - FN(override_return), + FN(getsockopt), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 271daad31f37..8a6c37762330 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1326,9 +1326,6 @@ EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp) { - if (fp->kprobe_override) - return false; - if (!array->owner_prog_type) { /* There's no owner yet where we could check for * compatibility. diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index bc464b8ec91e..4a942e2e753d 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4357,8 +4357,6 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env) prog->dst_needed = 1; if (insn->imm == BPF_FUNC_get_prandom_u32) bpf_user_rnd_init_once(); - if (insn->imm == BPF_FUNC_override_return) - prog->kprobe_override = 1; if (insn->imm == BPF_FUNC_tail_call) { /* If we tail call into other programs, we * cannot make any assumptions since they can diff --git a/kernel/events/core.c b/kernel/events/core.c index ac240d31b5bf..42d24bd64ea4 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8171,13 +8171,6 @@ static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) return -EINVAL; } - /* Kprobe override only works for kprobes, not uprobes. */ - if (prog->kprobe_override && - !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) { - bpf_prog_put(prog); - return -EINVAL; - } - if (is_tracepoint || is_syscall_tp) { int off = trace_event_get_offsets(event->tp_event); diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 9dc0deeaad2b..434c840e2d82 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -518,17 +518,6 @@ config FUNCTION_PROFILER If in doubt, say N. -config BPF_KPROBE_OVERRIDE - bool "Enable BPF programs to override a kprobed function" - depends on BPF_EVENTS - depends on KPROBES_ON_FTRACE - depends on HAVE_KPROBE_OVERRIDE - depends on DYNAMIC_FTRACE_WITH_REGS - default n - help - Allows BPF to override the execution of a probed function and - set a different return value. This is used for error injection. - config FTRACE_MCOUNT_RECORD def_bool y depends on DYNAMIC_FTRACE diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 1865b0d4cdeb..506efe6e8ed9 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -13,10 +13,6 @@ #include #include #include -#include -#include - -#include "trace_probe.h" #include "trace.h" u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); @@ -80,29 +76,6 @@ unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx) } EXPORT_SYMBOL_GPL(trace_call_bpf); -#ifdef CONFIG_BPF_KPROBE_OVERRIDE -BPF_CALL_2(bpf_override_return, struct pt_regs *, regs, unsigned long, rc) -{ - __this_cpu_write(bpf_kprobe_override, 1); - regs_set_return_value(regs, rc); - arch_ftrace_kprobe_override_function(regs); - return 0; -} -#else -BPF_CALL_2(bpf_override_return, struct pt_regs *, regs, unsigned long, rc) -{ - return -EINVAL; -} -#endif - -static const struct bpf_func_proto bpf_override_return_proto = { - .func = bpf_override_return, - .gpl_only = true, - .ret_type = RET_INTEGER, - .arg1_type = ARG_PTR_TO_CTX, - .arg2_type = ARG_ANYTHING, -}; - BPF_CALL_3(bpf_probe_read, void *, dst, u32, size, const void *, unsafe_ptr) { int ret; @@ -578,10 +551,6 @@ static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func return &bpf_get_stackid_proto; case BPF_FUNC_perf_event_read_value: return &bpf_perf_event_read_value_proto; - case BPF_FUNC_override_return: - pr_warn_ratelimited("%s[%d] is installing a program with bpf_override_return helper that may cause unexpected behavior!", - current->comm, task_pid_nr(current)); - return &bpf_override_return_proto; default: return tracing_func_proto(func_id); } @@ -797,10 +766,6 @@ int perf_event_attach_bpf_prog(struct perf_event *event, struct bpf_prog_array *new_array; int ret = -EEXIST; - /* Kprobe override only works for ftrace based kprobes. */ - if (prog->kprobe_override && !trace_kprobe_ftrace(event->tp_event)) - return -EINVAL; - mutex_lock(&bpf_event_mutex); if (event->prog) diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 8e3c9ec1faf7..abf92e478cfb 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -42,7 +42,6 @@ struct trace_kprobe { (offsetof(struct trace_kprobe, tp.args) + \ (sizeof(struct probe_arg) * (n))) -DEFINE_PER_CPU(int, bpf_kprobe_override); static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk) { @@ -88,12 +87,6 @@ static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk) return nhit; } -int trace_kprobe_ftrace(struct trace_event_call *call) -{ - struct trace_kprobe *tk = (struct trace_kprobe *)call->data; - return kprobe_ftrace(&tk->rp.kp); -} - static int register_kprobe_event(struct trace_kprobe *tk); static int unregister_kprobe_event(struct trace_kprobe *tk); @@ -1177,7 +1170,7 @@ static int kretprobe_event_define_fields(struct trace_event_call *event_call) #ifdef CONFIG_PERF_EVENTS /* Kprobe profile handler */ -static int +static void kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs) { struct trace_event_call *call = &tk->tp.call; @@ -1186,29 +1179,12 @@ kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs) int size, __size, dsize; int rctx; - if (bpf_prog_array_valid(call)) { - int ret; - - ret = trace_call_bpf(call, regs); - - /* - * We need to check and see if we modified the pc of the - * pt_regs, and if so clear the kprobe and return 1 so that we - * don't do the instruction skipping. Also reset our state so - * we are clean the next pass through. - */ - if (__this_cpu_read(bpf_kprobe_override)) { - __this_cpu_write(bpf_kprobe_override, 0); - reset_current_kprobe(); - return 1; - } - if (!ret) - return 0; - } + if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs)) + return; head = this_cpu_ptr(call->perf_events); if (hlist_empty(head)) - return 0; + return; dsize = __get_data_size(&tk->tp, regs); __size = sizeof(*entry) + tk->tp.size + dsize; @@ -1217,14 +1193,13 @@ kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs) entry = perf_trace_buf_alloc(size, NULL, &rctx); if (!entry) - return 0; + return; entry->ip = (unsigned long)tk->rp.kp.addr; memset(&entry[1], 0, dsize); store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize); perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, head, NULL, NULL); - return 0; } NOKPROBE_SYMBOL(kprobe_perf_func); @@ -1300,7 +1275,6 @@ static int kprobe_register(struct trace_event_call *event, static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs) { struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp); - int ret = 0; raw_cpu_inc(*tk->nhit); @@ -1308,9 +1282,9 @@ static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs) kprobe_trace_func(tk, regs); #ifdef CONFIG_PERF_EVENTS if (tk->tp.flags & TP_FLAG_PROFILE) - ret = kprobe_perf_func(tk, regs); + kprobe_perf_func(tk, regs); #endif - return ret; + return 0; /* We don't tweek kernel, so just return 0 */ } NOKPROBE_SYMBOL(kprobe_dispatcher); diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index adbb3f7d1fb5..903273c93e61 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -253,7 +253,6 @@ struct symbol_cache; unsigned long update_symbol_cache(struct symbol_cache *sc); void free_symbol_cache(struct symbol_cache *sc); struct symbol_cache *alloc_symbol_cache(const char *sym, long offset); -int trace_kprobe_ftrace(struct trace_event_call *call); #else /* uprobes do not support symbol fetch methods */ #define fetch_symbol_u8 NULL @@ -279,11 +278,6 @@ alloc_symbol_cache(const char *sym, long offset) { return NULL; } - -static inline int trace_kprobe_ftrace(struct trace_event_call *call) -{ - return 0; -} #endif /* CONFIG_KPROBE_EVENTS */ struct probe_arg { diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 87db0f9a4c15..3b4945c1eab0 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -15,7 +15,6 @@ hostprogs-y += tracex3 hostprogs-y += tracex4 hostprogs-y += tracex5 hostprogs-y += tracex6 -hostprogs-y += tracex7 hostprogs-y += test_probe_write_user hostprogs-y += trace_output hostprogs-y += lathist @@ -62,7 +61,6 @@ tracex3-objs := bpf_load.o $(LIBBPF) tracex3_user.o tracex4-objs := bpf_load.o $(LIBBPF) tracex4_user.o tracex5-objs := bpf_load.o $(LIBBPF) tracex5_user.o tracex6-objs := bpf_load.o $(LIBBPF) tracex6_user.o -tracex7-objs := bpf_load.o $(LIBBPF) tracex7_user.o load_sock_ops-objs := bpf_load.o $(LIBBPF) load_sock_ops.o test_probe_write_user-objs := bpf_load.o $(LIBBPF) test_probe_write_user_user.o trace_output-objs := bpf_load.o $(LIBBPF) trace_output_user.o @@ -106,7 +104,6 @@ always += tracex3_kern.o always += tracex4_kern.o always += tracex5_kern.o always += tracex6_kern.o -always += tracex7_kern.o always += sock_flags_kern.o always += test_probe_write_user_kern.o always += trace_output_kern.o @@ -161,7 +158,6 @@ HOSTLOADLIBES_tracex3 += -lelf HOSTLOADLIBES_tracex4 += -lelf -lrt HOSTLOADLIBES_tracex5 += -lelf HOSTLOADLIBES_tracex6 += -lelf -HOSTLOADLIBES_tracex7 += -lelf HOSTLOADLIBES_test_cgrp2_sock2 += -lelf HOSTLOADLIBES_load_sock_ops += -lelf HOSTLOADLIBES_test_probe_write_user += -lelf diff --git a/samples/bpf/test_override_return.sh b/samples/bpf/test_override_return.sh deleted file mode 100755 index e68b9ee6814b..000000000000 --- a/samples/bpf/test_override_return.sh +++ /dev/null @@ -1,15 +0,0 @@ -#!/bin/bash - -rm -f testfile.img -dd if=/dev/zero of=testfile.img bs=1M seek=1000 count=1 -DEVICE=$(losetup --show -f testfile.img) -mkfs.btrfs -f $DEVICE -mkdir tmpmnt -./tracex7 $DEVICE -if [ $? -eq 0 ] -then - echo "SUCCESS!" -else - echo "FAILED!" -fi -losetup -d $DEVICE diff --git a/samples/bpf/tracex7_kern.c b/samples/bpf/tracex7_kern.c deleted file mode 100644 index 1ab308a43e0f..000000000000 --- a/samples/bpf/tracex7_kern.c +++ /dev/null @@ -1,16 +0,0 @@ -#include -#include -#include -#include "bpf_helpers.h" - -SEC("kprobe/open_ctree") -int bpf_prog1(struct pt_regs *ctx) -{ - unsigned long rc = -12; - - bpf_override_return(ctx, rc); - return 0; -} - -char _license[] SEC("license") = "GPL"; -u32 _version SEC("version") = LINUX_VERSION_CODE; diff --git a/samples/bpf/tracex7_user.c b/samples/bpf/tracex7_user.c deleted file mode 100644 index 8a52ac492e8b..000000000000 --- a/samples/bpf/tracex7_user.c +++ /dev/null @@ -1,28 +0,0 @@ -#define _GNU_SOURCE - -#include -#include -#include -#include "libbpf.h" -#include "bpf_load.h" - -int main(int argc, char **argv) -{ - FILE *f; - char filename[256]; - char command[256]; - int ret; - - snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); - - if (load_bpf_file(filename)) { - printf("%s", bpf_log_buf); - return 1; - } - - snprintf(command, 256, "mount %s tmpmnt/", argv[1]); - f = popen(command, "r"); - ret = pclose(f); - - return ret ? 0 : 1; -} diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index adb66f78b674..e880ae6434ee 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -677,10 +677,6 @@ union bpf_attr { * @buf: buf to fill * @buf_size: size of the buf * Return : 0 on success or negative error code - * - * int bpf_override_return(pt_regs, rc) - * @pt_regs: pointer to struct pt_regs - * @rc: the return value to set */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -740,8 +736,7 @@ union bpf_attr { FN(xdp_adjust_meta), \ FN(perf_event_read_value), \ FN(perf_prog_read_value), \ - FN(getsockopt), \ - FN(override_return), + FN(getsockopt), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h index 33cb00e46c49..fd9a17fa8a8b 100644 --- a/tools/testing/selftests/bpf/bpf_helpers.h +++ b/tools/testing/selftests/bpf/bpf_helpers.h @@ -82,8 +82,7 @@ static int (*bpf_perf_event_read_value)(void *map, unsigned long long flags, static int (*bpf_perf_prog_read_value)(void *ctx, void *buf, unsigned int buf_size) = (void *) BPF_FUNC_perf_prog_read_value; -static int (*bpf_override_return)(void *ctx, unsigned long rc) = - (void *) BPF_FUNC_override_return; + /* llvm builtin functions that eBPF C program may use to * emit BPF_LD_ABS and BPF_LD_IND instructions -- 2.11.0