Bug #1166
Updated by Jonathan Rajotte Julien almost 6 years ago
Hi If lttng-sessiond terminates unexpectedly after truncating the metadata file from --shm-path path (when doing metadata regenerate), afterwards when trying to recover the trace buffers using lttng-crash <- it Bus error (core dumped). This translates to: <pre> $ lttng create s1 --shm-path=/tmp/test-lttng $ lttng enable-event -u -a -s s1 $ lttng start $ <path>/lttng-tools/tests/utils/testapp/gen-ust-events/gen-ust-events $ pkill -9 "lttng-" # 1 $ cp /dev/null /tmp/test/s1-*/ust/uid/1000/64-bit/metadata # 2 - 1 and 2 simulate sessiond crash immediately after ftruncate() during metadata regenerate $ lttng-crash --viewer=babeltrace /tmp/test-lttng/ </pre> A possible fix is : <pre> --- src/bin/lttng-crash/lttng-crash.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/src/bin/lttng-crash/lttng-crash.c b/src/bin/lttng-crash/lttng-crash.c index ba28af9..0fb93fd 100644 --- a/src/bin/lttng-crash/lttng-crash.c +++ b/src/bin/lttng-crash/lttng-crash.c @@ -490,7 +490,8 @@ int check_magic(const uint8_t *magic) } static -int get_crash_layout(struct lttng_crash_layout *layout, int fd) +int get_crash_layout(struct lttng_crash_layout *layout, int fd, + const char *input_path, const char *input_file) { char *map; int ret = 0, unmapret; @@ -501,7 +502,13 @@ int get_crash_layout(struct lttng_crash_layout *layout, int fd) const struct crash_abi_unknown *abi; uint16_t endian; enum lttng_crash_type layout_type; + struct stat sb; + fstat(fd, &sb); + if (sb.st_size < RB_CRASH_DUMP_ABI_LEN) { + ERR("File truncated: %s/%s", input_path, input_file); + return -1; + } map = mmap(NULL, RB_CRASH_DUMP_ABI_LEN, PROT_READ, MAP_PRIVATE, fd, 0); if (map == MAP_FAILED) { @@ -830,7 +837,7 @@ int extract_file(int output_dir_fd, const char *output_file, } /* Query the crash ABI layout */ - ret = get_crash_layout(&layout, fd_src); + ret = get_crash_layout(&layout, fd_src, input_path, input_file); if (ret) { goto close_src; } -- 1.9.1 </pre>