diff options
| -rw-r--r-- | debuggerd/arm/machine.c | 70 | ||||
| -rw-r--r-- | debuggerd/debuggerd.c | 27 | ||||
| -rw-r--r-- | debuggerd/utility.c | 18 | ||||
| -rw-r--r-- | debuggerd/utility.h | 4 |
4 files changed, 112 insertions, 7 deletions
diff --git a/debuggerd/arm/machine.c b/debuggerd/arm/machine.c index 88bf054..58a7839 100644 --- a/debuggerd/arm/machine.c +++ b/debuggerd/arm/machine.c @@ -50,6 +50,74 @@ extern int unwind_backtrace_with_ptrace(int tfd, pid_t pid, mapinfo *map, int *frame0_pc_sane, bool at_fault); +/* + * If this isn't clearly a null pointer dereference, dump the + * /proc/maps entries near the fault address. + */ +static void show_nearby_maps(int tfd, int pid, mapinfo *map) +{ + siginfo_t si; + + memset(&si, 0, sizeof(si)); + if (ptrace(PTRACE_GETSIGINFO, pid, 0, &si)) { + _LOG(tfd, false, "cannot get siginfo: %s\n", strerror(errno)); + return; + } + if (!signal_has_address(si.si_signo)) + return; + + uintptr_t addr = (uintptr_t) si.si_addr; + addr &= ~0xfff; /* round to 4K page boundary */ + if (addr == 0) /* null-pointer deref */ + return; + + _LOG(tfd, false, "\nmemory map around addr %08x:\n", si.si_addr); + + /* + * Search for a match, or for a hole where the match would be. The list + * is backward from the file content, so it starts at high addresses. + */ + bool found = false; + mapinfo *next = NULL; + mapinfo *prev = NULL; + while (map != NULL) { + if (addr >= map->start && addr < map->end) { + found = true; + next = map->next; + break; + } else if (addr >= map->end) { + /* map would be between "prev" and this entry */ + next = map; + map = NULL; + break; + } + + prev = map; + map = map->next; + } + + /* + * Show "next" then "match" then "prev" so that the addresses appear in + * ascending order (like /proc/pid/maps). + */ + if (next != NULL) { + _LOG(tfd, false, "%08x-%08x %s\n", next->start, next->end, next->name); + } else { + _LOG(tfd, false, "(no map below)\n"); + } + if (map != NULL) { + _LOG(tfd, false, "%08x-%08x %s\n", map->start, map->end, map->name); + } else { + _LOG(tfd, false, "(no map for address)\n"); + } + if (prev != NULL) { + _LOG(tfd, false, "%08x-%08x %s\n", prev->start, prev->end, prev->name); + } else { + _LOG(tfd, false, "(no map above)\n"); + } +} + + void dump_stack_and_code(int tfd, int pid, mapinfo *map, int unwind_depth, unsigned int sp_list[], bool at_fault) @@ -123,6 +191,8 @@ void dump_stack_and_code(int tfd, int pid, mapinfo *map, } } + show_nearby_maps(tfd, pid, map); + p = sp - 64; if (p > sp) p = 0; diff --git a/debuggerd/debuggerd.c b/debuggerd/debuggerd.c index d03c214..97a6b9e 100644 --- a/debuggerd/debuggerd.c +++ b/debuggerd/debuggerd.c @@ -70,14 +70,17 @@ mapinfo *parse_maps_line(char *line) mapinfo *mi; int len = strlen(line); - if(len < 1) return 0; + if (len < 1) return 0; /* not expected */ line[--len] = 0; - if(len < 50) return 0; - if(line[20] != 'x') return 0; + if (len < 50) { + mi = malloc(sizeof(mapinfo) + 1); + } else { + mi = malloc(sizeof(mapinfo) + (len - 47)); + } + if (mi == 0) return 0; - mi = malloc(sizeof(mapinfo) + (len - 47)); - if(mi == 0) return 0; + mi->isExecutable = (line[20] == 'x'); mi->start = strtoul(line, 0, 16); mi->end = strtoul(line + 9, 0, 16); @@ -87,7 +90,11 @@ mapinfo *parse_maps_line(char *line) mi->exidx_start = mi->exidx_end = 0; mi->symbols = 0; mi->next = 0; - strcpy(mi->name, line + 49); + if (len < 50) { + mi->name[0] = '\0'; + } else { + strcpy(mi->name, line + 49); + } return mi; } @@ -165,11 +172,14 @@ void dump_fault_addr(int tfd, int pid, int sig) memset(&si, 0, sizeof(si)); if(ptrace(PTRACE_GETSIGINFO, pid, 0, &si)){ _LOG(tfd, false, "cannot get siginfo: %s\n", strerror(errno)); - } else { + } else if (signal_has_address(sig)) { _LOG(tfd, false, "signal %d (%s), code %d (%s), fault addr %08x\n", sig, get_signame(sig), si.si_code, get_sigcode(sig, si.si_code), si.si_addr); + } else { + _LOG(tfd, false, "signal %d (%s), code %d (%s), fault addr --------\n", + sig, get_signame(sig), si.si_code, get_sigcode(sig, si.si_code)); } } @@ -199,6 +209,9 @@ static void parse_elf_info(mapinfo *milist, pid_t pid) { mapinfo *mi; for (mi = milist; mi != NULL; mi = mi->next) { + if (!mi->isExecutable) + continue; + Elf32_Ehdr ehdr; memset(&ehdr, 0, sizeof(Elf32_Ehdr)); diff --git a/debuggerd/utility.c b/debuggerd/utility.c index 2afdb46..409209c 100644 --- a/debuggerd/utility.c +++ b/debuggerd/utility.c @@ -17,6 +17,7 @@ #include <sys/ptrace.h> #include <sys/exec_elf.h> +#include <signal.h> #include <assert.h> #include <string.h> #include <errno.h> @@ -82,3 +83,20 @@ const mapinfo *pc_to_mapinfo(mapinfo *mi, unsigned pc, unsigned *rel_pc) } return NULL; } + +/* + * Returns true if the specified signal has an associated address (i.e. it + * sets siginfo_t.si_addr). + */ +bool signal_has_address(int sig) +{ + switch (sig) { + case SIGILL: + case SIGFPE: + case SIGSEGV: + case SIGBUS: + return true; + default: + return false; + } +} diff --git a/debuggerd/utility.h b/debuggerd/utility.h index 45e2067..4a935d2 100644 --- a/debuggerd/utility.h +++ b/debuggerd/utility.h @@ -36,6 +36,7 @@ typedef struct mapinfo { unsigned exidx_start; unsigned exidx_end; struct symbol_table *symbols; + bool isExecutable; char name[]; } mapinfo; @@ -56,6 +57,9 @@ const char *map_to_name(mapinfo *mi, unsigned pc, const char* def); /* Log information onto the tombstone */ extern void _LOG(int tfd, bool in_tombstone_only, const char *fmt, ...); +/* Determine whether si_addr is valid for this signal */ +bool signal_has_address(int sig); + #define LOG(fmt...) _LOG(-1, 0, fmt) /* Set to 1 for normal debug traces */ |