Messages in this thread | | | Date | Tue, 22 Nov 2022 09:47:49 +0800 | Subject | Re: [PATCH 1/4] kernel/trace: Introduce new APIs to process probe arguments | From | Song Chen <> |
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Hi,
在 2022/11/22 06:01, Masami Hiramatsu (Google) 写道: > Hi Song, > > On Wed, 16 Nov 2022 20:25:07 +0800 > Song Chen <chensong_2000@189.cn> wrote: > >> Introduce 3 new APIs: >> 1. trace_probe_get_data_size: get arguments' data size >> 2. trace_probe_store_args: store aruguments into ring buffer >> 3. trace_probe_print_args: print arguments into trace file > > Ah, I meant that split the patches into > > Introduce trace_probe_get_data_size() and use it in *probes > Introduce trace_probe_store_args() and use it in *probes > Introduce trace_probe_print_args and use it in *probes > > Then we can easily understand by its meaning. > > Can you reform this series again? > > Thank you, >
understood, will do , thanks.
/Song
>> >> Those APIs are going to merge similar implementations respectively >> in kprobe/uprobe/eprobe. >> >> Signed-off-by: Song Chen <chensong_2000@189.cn> >> --- >> kernel/trace/trace_probe.c | 305 ++++++++++++++++++++++++++++++ >> kernel/trace/trace_probe.h | 5 + >> kernel/trace/trace_probe_common.h | 69 +++++++ >> kernel/trace/trace_probe_user.h | 95 ++++++++++ >> 4 files changed, 474 insertions(+) >> create mode 100644 kernel/trace/trace_probe_common.h >> create mode 100644 kernel/trace/trace_probe_user.h >> >> diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c >> index 36dff277de46..303f057bd2f7 100644 >> --- a/kernel/trace/trace_probe.c >> +++ b/kernel/trace/trace_probe.c >> @@ -12,6 +12,9 @@ >> #define pr_fmt(fmt) "trace_probe: " fmt >> >> #include "trace_probe.h" >> +#include "trace_probe_kernel.h" >> +#include "trace_probe_user.h" >> +#include "trace_probe_common.h" >> >> #undef C >> #define C(a, b) b >> @@ -1218,3 +1221,305 @@ int trace_probe_create(const char *raw_command, int (*createfn)(int, const char >> >> return ret; >> } >> + >> +/* From the 2nd stage, routine is same */ >> +static nokprobe_inline int >> +process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val, >> + void *dest, void *base, int flags) >> +{ >> + struct fetch_insn *s3 = NULL; >> + int total = 0, ret = 0, i = 0; >> + u32 loc = 0; >> + unsigned long lval = val; >> + int is_uprobe = flags & TRACE_EVENT_FL_UPROBE; >> + >> +stage2: >> + /* 2nd stage: dereference memory if needed */ >> + do { >> + if (code->op == FETCH_OP_DEREF) { >> + lval = val; >> + ret = probe_mem_read(&val, (void *)val + code->offset, >> + sizeof(val)); >> + } else if (code->op == FETCH_OP_UDEREF) { >> + lval = val; >> + ret = probe_mem_read_user(&val, >> + (void *)val + code->offset, sizeof(val)); >> + } else >> + break; >> + if (ret) >> + return ret; >> + code++; >> + } while (1); >> + >> + s3 = code; >> +stage3: >> + /* 3rd stage: store value to buffer */ >> + if (unlikely(!dest)) { >> + if (code->op == FETCH_OP_ST_STRING) { >> + if (is_uprobe) >> + ret = user_fetch_store_strlen(val + code->offset); >> + else >> + ret = kern_fetch_store_strlen(val + code->offset); >> + code++; >> + goto array; >> + } else if (code->op == FETCH_OP_ST_USTRING) { >> + if (is_uprobe) >> + ret += user_fetch_store_strlen_user(val + code->offset); >> + else >> + ret += kern_fetch_store_strlen_user(val + code->offset); >> + code++; >> + goto array; >> + } else >> + return -EILSEQ; >> + } >> + >> + switch (code->op) { >> + case FETCH_OP_ST_RAW: >> + fetch_store_raw(val, code, dest); >> + break; >> + case FETCH_OP_ST_MEM: >> + probe_mem_read(dest, (void *)val + code->offset, code->size); >> + break; >> + case FETCH_OP_ST_UMEM: >> + probe_mem_read_user(dest, (void *)val + code->offset, code->size); >> + break; >> + case FETCH_OP_ST_STRING: >> + loc = *(u32 *)dest; >> + if (is_uprobe) >> + ret = user_fetch_store_string(val + code->offset, dest, base); >> + else >> + ret = kern_fetch_store_string(val + code->offset, dest, base); >> + break; >> + case FETCH_OP_ST_USTRING: >> + loc = *(u32 *)dest; >> + if (is_uprobe) >> + ret = user_fetch_store_string_user(val + code->offset, dest, base); >> + else >> + ret = kern_fetch_store_string_user(val + code->offset, dest, base); >> + break; >> + default: >> + return -EILSEQ; >> + } >> + code++; >> + >> + /* 4th stage: modify stored value if needed */ >> + if (code->op == FETCH_OP_MOD_BF) { >> + fetch_apply_bitfield(code, dest); >> + code++; >> + } >> + >> +array: >> + /* the last stage: Loop on array */ >> + if (code->op == FETCH_OP_LP_ARRAY) { >> + total += ret; >> + if (++i < code->param) { >> + code = s3; >> + if (s3->op != FETCH_OP_ST_STRING && >> + s3->op != FETCH_OP_ST_USTRING) { >> + dest += s3->size; >> + val += s3->size; >> + goto stage3; >> + } >> + code--; >> + val = lval + sizeof(char *); >> + if (dest) { >> + dest += sizeof(u32); >> + *(u32 *)dest = update_data_loc(loc, ret); >> + } >> + goto stage2; >> + } >> + code++; >> + ret = total; >> + } >> + >> + return code->op == FETCH_OP_END ? ret : -EILSEQ; >> +} >> + >> +static unsigned long get_event_field(struct fetch_insn *code, void *rec) >> +{ >> + struct ftrace_event_field *field = code->data; >> + unsigned long val; >> + void *addr; >> + >> + addr = rec + field->offset; >> + >> + if (is_string_field(field)) { >> + switch (field->filter_type) { >> + case FILTER_DYN_STRING: >> + val = (unsigned long)(rec + (*(unsigned int *)addr & 0xffff)); >> + break; >> + case FILTER_RDYN_STRING: >> + val = (unsigned long)(addr + (*(unsigned int *)addr & 0xffff)); >> + break; >> + case FILTER_STATIC_STRING: >> + val = (unsigned long)addr; >> + break; >> + case FILTER_PTR_STRING: >> + val = (unsigned long)(*(char *)addr); >> + break; >> + default: >> + WARN_ON_ONCE(1); >> + return 0; >> + } >> + return val; >> + } >> + >> + switch (field->size) { >> + case 1: >> + if (field->is_signed) >> + val = *(char *)addr; >> + else >> + val = *(unsigned char *)addr; >> + break; >> + case 2: >> + if (field->is_signed) >> + val = *(short *)addr; >> + else >> + val = *(unsigned short *)addr; >> + break; >> + case 4: >> + if (field->is_signed) >> + val = *(int *)addr; >> + else >> + val = *(unsigned int *)addr; >> + break; >> + default: >> + if (field->is_signed) >> + val = *(long *)addr; >> + else >> + val = *(unsigned long *)addr; >> + break; >> + } >> + return val; >> +} >> + >> +/* Note that we don't verify it, since the code does not come from user space */ >> +static int >> +process_fetch_insn(struct fetch_insn *code, void *rec, void *dest, >> + void *base, int flags) >> +{ >> + struct pt_regs *regs = rec; >> + unsigned long val; >> + int is_uprobe = flags & TRACE_EVENT_FL_UPROBE; >> + >> +retry: >> + /* 1st stage: get value from context */ >> + switch (code->op) { >> + case FETCH_OP_REG: >> + val = regs_get_register(regs, code->param); >> + break; >> + case FETCH_OP_STACK: >> + if (is_uprobe) >> + val = get_user_stack_nth(regs, code->param); >> + else >> + val = regs_get_kernel_stack_nth(regs, code->param); >> + break; >> + case FETCH_OP_STACKP: >> + if (is_uprobe) >> + val = user_stack_pointer(regs); >> + else >> + val = kernel_stack_pointer(regs); >> + break; >> + case FETCH_OP_RETVAL: >> + val = regs_return_value(regs); >> + break; >> + case FETCH_OP_IMM: >> + val = code->immediate; >> + break; >> + case FETCH_OP_COMM: >> + val = (unsigned long)current->comm; >> + break; >> + case FETCH_OP_DATA: >> + val = (unsigned long)code->data; >> + break; >> +#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API >> + case FETCH_OP_ARG: >> + val = regs_get_kernel_argument(regs, code->param); >> + break; >> +#endif >> + case FETCH_NOP_SYMBOL: /* Ignore a place holder */ >> + code++; >> + goto retry; >> + case FETCH_OP_TP_ARG: >> + val = get_event_field(code, rec); >> + break; >> + default: >> + return -EILSEQ; >> + } >> + code++; >> + >> + return process_fetch_insn_bottom(code, val, dest, base, flags); >> +} >> +NOKPROBE_SYMBOL(process_fetch_insn) >> + >> +/* Sum up total data length for dynamic arrays (strings) */ >> +int trace_probe_get_data_size(struct trace_probe *tp, struct pt_regs *regs) >> +{ >> + struct probe_arg *arg; >> + int i, len, ret = 0; >> + struct trace_event_call *call = trace_probe_event_call(tp); >> + >> + for (i = 0; i < tp->nr_args; i++) { >> + arg = tp->args + i; >> + if (unlikely(arg->dynamic)) { >> + len = process_fetch_insn(arg->code, regs, NULL, NULL, call->flags); >> + if (len > 0) >> + ret += len; >> + } >> + } >> + >> + return ret; >> +} >> + >> +void trace_probe_store_args(void *data, struct trace_probe *tp, void *rec, >> + int header_size, int maxlen) >> +{ >> + struct probe_arg *arg; >> + void *base = data - header_size; >> + void *dyndata = data + tp->size; >> + u32 *dl; /* Data location */ >> + int ret, i; >> + struct trace_event_call *call = trace_probe_event_call(tp); >> + >> + for (i = 0; i < tp->nr_args; i++) { >> + arg = tp->args + i; >> + dl = data + arg->offset; >> + /* Point the dynamic data area if needed */ >> + if (unlikely(arg->dynamic)) >> + *dl = make_data_loc(maxlen, dyndata - base); >> + ret = process_fetch_insn(arg->code, rec, dl, base, call->flags); >> + if (unlikely(ret < 0 && arg->dynamic)) { >> + *dl = make_data_loc(0, dyndata - base); >> + } else { >> + dyndata += ret; >> + maxlen -= ret; >> + } >> + } >> +} >> + >> +int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_args, >> + u8 *data, void *field) >> +{ >> + void *p; >> + int i, j; >> + >> + for (i = 0; i < nr_args; i++) { >> + struct probe_arg *a = args + i; >> + >> + trace_seq_printf(s, " %s=", a->name); >> + if (likely(!a->count)) { >> + if (!a->type->print(s, data + a->offset, field)) >> + return -ENOMEM; >> + continue; >> + } >> + trace_seq_putc(s, '{'); >> + p = data + a->offset; >> + for (j = 0; j < a->count; j++) { >> + if (!a->type->print(s, p, field)) >> + return -ENOMEM; >> + trace_seq_putc(s, j == a->count - 1 ? '}' : ','); >> + p += a->type->size; >> + } >> + } >> + return 0; >> +} >> diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h >> index de38f1c03776..4f044047b748 100644 >> --- a/kernel/trace/trace_probe.h >> +++ b/kernel/trace/trace_probe.h >> @@ -343,6 +343,11 @@ int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b); >> bool trace_probe_match_command_args(struct trace_probe *tp, >> int argc, const char **argv); >> int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **)); >> +int trace_probe_get_data_size(struct trace_probe *tp, struct pt_regs *regs); >> +void trace_probe_store_args(void *data, struct trace_probe *tp, void *rec, >> + int header_size, int maxlen); >> +int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_args, >> + u8 *data, void *field); >> >> #define trace_probe_for_each_link(pos, tp) \ >> list_for_each_entry(pos, &(tp)->event->files, list) >> diff --git a/kernel/trace/trace_probe_common.h b/kernel/trace/trace_probe_common.h >> new file mode 100644 >> index 000000000000..b8d77447fe0c >> --- /dev/null >> +++ b/kernel/trace/trace_probe_common.h >> @@ -0,0 +1,69 @@ >> +/* SPDX-License-Identifier: GPL-2.0 */ >> +#ifndef __TRACE_PROBE_COMMON_H_ >> +#define __TRACE_PROBE_COMMON_H_ >> + >> +#define FAULT_STRING "(fault)" >> + >> +static nokprobe_inline void >> +fetch_store_raw(unsigned long val, struct fetch_insn *code, void *buf) >> +{ >> + switch (code->size) { >> + case 1: >> + *(u8 *)buf = (u8)val; >> + break; >> + case 2: >> + *(u16 *)buf = (u16)val; >> + break; >> + case 4: >> + *(u32 *)buf = (u32)val; >> + break; >> + case 8: >> + //TBD: 32bit signed >> + *(u64 *)buf = (u64)val; >> + break; >> + default: >> + *(unsigned long *)buf = val; >> + } >> +} >> + >> +static nokprobe_inline void >> +fetch_apply_bitfield(struct fetch_insn *code, void *buf) >> +{ >> + switch (code->basesize) { >> + case 1: >> + *(u8 *)buf <<= code->lshift; >> + *(u8 *)buf >>= code->rshift; >> + break; >> + case 2: >> + *(u16 *)buf <<= code->lshift; >> + *(u16 *)buf >>= code->rshift; >> + break; >> + case 4: >> + *(u32 *)buf <<= code->lshift; >> + *(u32 *)buf >>= code->rshift; >> + break; >> + case 8: >> + *(u64 *)buf <<= code->lshift; >> + *(u64 *)buf >>= code->rshift; >> + break; >> + } >> +} >> + >> +static nokprobe_inline int >> +probe_mem_read_user(void *dest, void *src, size_t size) >> +{ >> + const void __user *uaddr = (__force const void __user *)src; >> + >> + return copy_from_user_nofault(dest, uaddr, size); >> +} >> + >> +static nokprobe_inline int >> +probe_mem_read(void *dest, void *src, size_t size) >> +{ >> +#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE >> + if ((unsigned long)src < TASK_SIZE) >> + return probe_mem_read_user(dest, src, size); >> +#endif >> + return copy_from_kernel_nofault(dest, src, size); >> +} >> +#endif /* __TRACE_PROBE_COMMON_H_ */ >> diff --git a/kernel/trace/trace_probe_user.h b/kernel/trace/trace_probe_user.h >> new file mode 100644 >> index 000000000000..2104ccb44d56 >> --- /dev/null >> +++ b/kernel/trace/trace_probe_user.h >> @@ -0,0 +1,95 @@ >> +/* SPDX-License-Identifier: GPL-2.0 */ >> +#ifndef __TRACE_PROBE_USER_H_ >> +#define __TRACE_PROBE_USER_H_ >> + >> +#define FAULT_STRING "(fault)" >> + >> +/* >> + * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max >> + * length and relative data location. >> + */ >> +static nokprobe_inline int >> +user_fetch_store_string(unsigned long addr, void *dest, void *base) >> +{ >> + long ret; >> + u32 loc = *(u32 *)dest; >> + int maxlen = get_loc_len(loc); >> + u8 *dst = get_loc_data(dest, base); >> + void __user *src = (void __force __user *) addr; >> + >> + if (unlikely(!maxlen)) >> + return -ENOMEM; >> + >> + if (addr == FETCH_TOKEN_COMM) >> + ret = strlcpy(dst, current->comm, maxlen); >> + else >> + ret = strncpy_from_user(dst, src, maxlen); >> + if (ret >= 0) { >> + if (ret == maxlen) >> + dst[ret - 1] = '\0'; >> + else >> + /* >> + * Include the terminating null byte. In this case it >> + * was copied by strncpy_from_user but not accounted >> + * for in ret. >> + */ >> + ret++; >> + *(u32 *)dest = make_data_loc(ret, (void *)dst - base); >> + } >> + >> + return ret; >> +} >> + >> +static nokprobe_inline int >> +user_fetch_store_string_user(unsigned long addr, void *dest, void *base) >> +{ >> + return user_fetch_store_string(addr, dest, base); >> +} >> + >> +/* Return the length of string -- including null terminal byte */ >> +static nokprobe_inline int >> +user_fetch_store_strlen(unsigned long addr) >> +{ >> + int len; >> + void __user *vaddr = (void __force __user *) addr; >> + >> + if (addr == FETCH_TOKEN_COMM) >> + len = strlen(current->comm) + 1; >> + else >> + len = strnlen_user(vaddr, MAX_STRING_SIZE); >> + >> + return (len > MAX_STRING_SIZE) ? 0 : len; >> +} >> + >> +static nokprobe_inline int >> +user_fetch_store_strlen_user(unsigned long addr) >> +{ >> + return user_fetch_store_strlen(addr); >> +} >> + >> +#ifdef CONFIG_STACK_GROWSUP >> +static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n) >> +{ >> + return addr - (n * sizeof(long)); >> +} >> +#else >> +static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n) >> +{ >> + return addr + (n * sizeof(long)); >> +} >> +#endif >> + >> +static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n) >> +{ >> + unsigned long ret; >> + unsigned long addr = user_stack_pointer(regs); >> + >> + addr = adjust_stack_addr(addr, n); >> + >> + if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret))) >> + return 0; >> + >> + return ret; >> +} >> + >> +#endif /* __TRACE_PROBE_USER_H_ */ >> -- >> 2.25.1 >> > >
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