From 9178412ddf5a98feba0ad3986111c5ad10eb9e59 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Wed, 25 Apr 2018 21:19:01 +0900 Subject: [PATCH] tracing: probeevent: Return consumed bytes of dynamic area Cleanup string fetching routine so that returns the consumed bytes of dynamic area and store the string information as data_loc format instead of data_rloc. This simplifies the fetcharg loop. Link: http://lkml.kernel.org/r/152465874163.26224.12125143907501289031.stgit@devbox Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_kprobe.c | 57 +++++++++++++++--------------- kernel/trace/trace_probe.h | 26 ++++---------- kernel/trace/trace_probe_tmpl.h | 54 ++++++++++++++--------------- kernel/trace/trace_uprobe.c | 61 ++++++++++++++++----------------- 4 files changed, 88 insertions(+), 110 deletions(-) diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index dc1c638daf44..7e5064f8ab8f 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -853,8 +853,8 @@ static const struct file_operations kprobe_profile_ops = { /* Kprobe specific fetch functions */ /* Return the length of string -- including null terminal byte */ -static nokprobe_inline void -fetch_store_strlen(unsigned long addr, void *dest) +static nokprobe_inline int +fetch_store_strlen(unsigned long addr) { mm_segment_t old_fs; int ret, len = 0; @@ -872,47 +872,40 @@ fetch_store_strlen(unsigned long addr, void *dest) pagefault_enable(); set_fs(old_fs); - if (ret < 0) /* Failed to check the length */ - *(u32 *)dest = 0; - else - *(u32 *)dest = len; + return (ret < 0) ? ret : len; } /* * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max * length and relative data location. */ -static nokprobe_inline void -fetch_store_string(unsigned long addr, void *dest) +static nokprobe_inline int +fetch_store_string(unsigned long addr, void *dest, void *base) { - int maxlen = get_rloc_len(*(u32 *)dest); - u8 *dst = get_rloc_data(dest); + int maxlen = get_loc_len(*(u32 *)dest); + u8 *dst = get_loc_data(dest, base); long ret; - if (!maxlen) - return; - + if (unlikely(!maxlen)) + return -ENOMEM; /* * Try to get string again, since the string can be changed while * probing. */ ret = strncpy_from_unsafe(dst, (void *)addr, maxlen); - if (ret < 0) { /* Failed to fetch string */ - dst[0] = '\0'; - *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest)); - } else { - *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest)); - } + if (ret >= 0) + *(u32 *)dest = make_data_loc(ret, (void *)dst - base); + return ret; } /* 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, struct pt_regs *regs, void *dest, - bool pre) + void *base) { unsigned long val; - int ret; + int ret = 0; /* 1st stage: get value from context */ switch (code->op) { @@ -949,6 +942,13 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, } /* 3rd stage: store value to buffer */ + if (unlikely(!dest)) { + if (code->op == FETCH_OP_ST_STRING) + return fetch_store_strlen(val + code->offset); + else + return -EILSEQ; + } + switch (code->op) { case FETCH_OP_ST_RAW: fetch_store_raw(val, code, dest); @@ -957,10 +957,7 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, probe_kernel_read(dest, (void *)val + code->offset, code->size); break; case FETCH_OP_ST_STRING: - if (pre) - fetch_store_strlen(val + code->offset, dest); - else - fetch_store_string(val + code->offset, dest); + ret = fetch_store_string(val + code->offset, dest, base); break; default: return -EILSEQ; @@ -973,7 +970,7 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, code++; } - return code->op == FETCH_OP_END ? 0 : -EILSEQ; + return code->op == FETCH_OP_END ? ret : -EILSEQ; } NOKPROBE_SYMBOL(process_fetch_insn) @@ -1008,7 +1005,7 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs, entry = ring_buffer_event_data(event); entry->ip = (unsigned long)tk->rp.kp.addr; - store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize); + store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); event_trigger_unlock_commit_regs(trace_file, buffer, event, entry, irq_flags, pc, regs); @@ -1057,7 +1054,7 @@ __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, entry = ring_buffer_event_data(event); entry->func = (unsigned long)tk->rp.kp.addr; entry->ret_ip = (unsigned long)ri->ret_addr; - store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize); + store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); event_trigger_unlock_commit_regs(trace_file, buffer, event, entry, irq_flags, pc, regs); @@ -1203,7 +1200,7 @@ kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs) 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); + store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, head, NULL); return 0; @@ -1239,7 +1236,7 @@ kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, entry->func = (unsigned long)tk->rp.kp.addr; entry->ret_ip = (unsigned long)ri->ret_addr; - store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize); + store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, head, NULL); } diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index 5c262ed6347c..b6bdd82fa485 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -54,29 +54,15 @@ #define TP_FLAG_PROFILE 2 #define TP_FLAG_REGISTERED 4 +/* data_loc: data location, compatible with u32 */ +#define make_data_loc(len, offs) \ + (((u32)(len) << 16) | ((u32)(offs) & 0xffff)) +#define get_loc_len(dl) ((u32)(dl) >> 16) +#define get_loc_offs(dl) ((u32)(dl) & 0xffff) -/* data_rloc: data relative location, compatible with u32 */ -#define make_data_rloc(len, roffs) \ - (((u32)(len) << 16) | ((u32)(roffs) & 0xffff)) -#define get_rloc_len(dl) ((u32)(dl) >> 16) -#define get_rloc_offs(dl) ((u32)(dl) & 0xffff) - -/* - * Convert data_rloc to data_loc: - * data_rloc stores the offset from data_rloc itself, but data_loc - * stores the offset from event entry. - */ -#define convert_rloc_to_loc(dl, offs) ((u32)(dl) + (offs)) - -static nokprobe_inline void *get_rloc_data(u32 *dl) -{ - return (u8 *)dl + get_rloc_offs(*dl); -} - -/* For data_loc conversion */ static nokprobe_inline void *get_loc_data(u32 *dl, void *ent) { - return (u8 *)ent + get_rloc_offs(*dl); + return (u8 *)ent + get_loc_offs(*dl); } /* Printing function type */ diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h index c8a5272abf01..3b4aba6f84cc 100644 --- a/kernel/trace/trace_probe_tmpl.h +++ b/kernel/trace/trace_probe_tmpl.h @@ -48,24 +48,28 @@ fetch_apply_bitfield(struct fetch_insn *code, void *buf) } } -/* Define this for each callsite */ +/* + * This must be defined for each callsite. + * Return consumed dynamic data size (>= 0), or error (< 0). + * If dest is NULL, don't store result and return required dynamic data size. + */ static int process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, - void *dest, bool pre); + void *dest, void *base); /* Sum up total data length for dynamic arraies (strings) */ static nokprobe_inline int __get_data_size(struct trace_probe *tp, struct pt_regs *regs) { struct probe_arg *arg; - int i, ret = 0; - u32 len; + int i, len, ret = 0; for (i = 0; i < tp->nr_args; i++) { arg = tp->args + i; if (unlikely(arg->dynamic)) { - process_fetch_insn(arg->code, regs, &len, true); - ret += len; + len = process_fetch_insn(arg->code, regs, NULL, NULL); + if (len > 0) + ret += len; } } @@ -74,34 +78,26 @@ __get_data_size(struct trace_probe *tp, struct pt_regs *regs) /* Store the value of each argument */ static nokprobe_inline void -store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs, - u8 *data, int maxlen) +store_trace_args(void *data, struct trace_probe *tp, struct pt_regs *regs, + int header_size, int maxlen) { struct probe_arg *arg; - u32 end = tp->size; - u32 *dl; /* Data (relative) location */ - int i; + void *base = data - header_size; + void *dyndata = data + tp->size; + u32 *dl; /* Data location */ + int ret, i; for (i = 0; i < tp->nr_args; i++) { arg = tp->args + i; - if (unlikely(arg->dynamic)) { - /* - * First, we set the relative location and - * maximum data length to *dl - */ - dl = (u32 *)(data + arg->offset); - *dl = make_data_rloc(maxlen, end - arg->offset); - /* Then try to fetch string or dynamic array data */ - process_fetch_insn(arg->code, regs, dl, false); - /* Reduce maximum length */ - end += get_rloc_len(*dl); - maxlen -= get_rloc_len(*dl); - /* Trick here, convert data_rloc to data_loc */ - *dl = convert_rloc_to_loc(*dl, ent_size + arg->offset); - } else - /* Just fetching data normally */ - process_fetch_insn(arg->code, regs, data + arg->offset, - false); + 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, regs, dl, base); + if (unlikely(ret < 0 && arg->dynamic)) + *dl = make_data_loc(0, dyndata - base); + else + dyndata += ret; } } diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index 7772fec84c12..08ad51c8ebc0 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -111,43 +111,38 @@ probe_user_read(void *dest, void *src, size_t size) * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max * length and relative data location. */ -static nokprobe_inline void -fetch_store_string(unsigned long addr, void *dest) +static nokprobe_inline int +fetch_store_string(unsigned long addr, void *dest, void *base) { long ret; - u32 rloc = *(u32 *)dest; - int maxlen = get_rloc_len(rloc); - u8 *dst = get_rloc_data(dest); + 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 (!maxlen) - return; + if (unlikely(!maxlen)) + return -ENOMEM; ret = strncpy_from_user(dst, src, maxlen); - if (ret == maxlen) - dst[--ret] = '\0'; - - if (ret < 0) { /* Failed to fetch string */ - ((u8 *)get_rloc_data(dest))[0] = '\0'; - *(u32 *)dest = make_data_rloc(0, get_rloc_offs(rloc)); - } else { - *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(rloc)); + if (ret >= 0) { + if (ret == maxlen) + dst[ret - 1] = '\0'; + *(u32 *)dest = make_data_loc(ret, (void *)dst - base); } + + return ret; } /* Return the length of string -- including null terminal byte */ -static nokprobe_inline void -fetch_store_strlen(unsigned long addr, void *dest) +static nokprobe_inline int +fetch_store_strlen(unsigned long addr) { int len; void __user *vaddr = (void __force __user *) addr; len = strnlen_user(vaddr, MAX_STRING_SIZE); - if (len == 0 || len > MAX_STRING_SIZE) /* Failed to check length */ - *(u32 *)dest = 0; - else - *(u32 *)dest = len; + return (len > MAX_STRING_SIZE) ? 0 : len; } static unsigned long translate_user_vaddr(unsigned long file_offset) @@ -164,10 +159,10 @@ static unsigned long translate_user_vaddr(unsigned long file_offset) /* 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, struct pt_regs *regs, void *dest, - bool pre) + void *base) { unsigned long val; - int ret; + int ret = 0; /* 1st stage: get value from context */ switch (code->op) { @@ -204,18 +199,22 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, } /* 3rd stage: store value to buffer */ + if (unlikely(!dest)) { + if (code->op == FETCH_OP_ST_STRING) + return fetch_store_strlen(val + code->offset); + else + return -EILSEQ; + } + switch (code->op) { case FETCH_OP_ST_RAW: fetch_store_raw(val, code, dest); break; case FETCH_OP_ST_MEM: - probe_user_read(dest, (void *)val + code->offset, code->size); + probe_kernel_read(dest, (void *)val + code->offset, code->size); break; case FETCH_OP_ST_STRING: - if (pre) - fetch_store_strlen(val + code->offset, dest); - else - fetch_store_string(val + code->offset, dest); + ret = fetch_store_string(val + code->offset, dest, base); break; default: return -EILSEQ; @@ -228,7 +227,7 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, code++; } - return code->op == FETCH_OP_END ? 0 : -EILSEQ; + return code->op == FETCH_OP_END ? ret : -EILSEQ; } NOKPROBE_SYMBOL(process_fetch_insn) @@ -1300,7 +1299,7 @@ static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs) esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); ucb = uprobe_buffer_get(); - store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize); + store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize); if (tu->tp.flags & TP_FLAG_TRACE) ret |= uprobe_trace_func(tu, regs, ucb, dsize); @@ -1335,7 +1334,7 @@ static int uretprobe_dispatcher(struct uprobe_consumer *con, esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); ucb = uprobe_buffer_get(); - store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize); + store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize); if (tu->tp.flags & TP_FLAG_TRACE) uretprobe_trace_func(tu, func, regs, ucb, dsize); -- 2.30.2