Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider: - [Medium] NULL pointer dereference and crash when the implicitly generated `--no-symvers` option is passed. - [Medium] The fallback file resolution logic incorrectly concatenates absolute paths to the kernel root directory, resulting in malformed paths and unintended file resolution. - [Low] Misleading error diagnostics for custom path failures. --
commit ad4674adedd0ef34b67a931273e6e044219ae8b0 Author: Joe Lawrence <[email protected]> objtool/klp: add --symvers option to klp diff This commit adds a --symvers (-s) option to klp diff that allows specifying a custom path to Module.symvers. The change aims to support out-of-tree module patching by decoupling the tool from the default Module.symvers location while preserving the existing fallback detection logic. > diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c > --- a/tools/objtool/klp-diff.c > +++ b/tools/objtool/klp-diff.c [ ... ] > @@ -46,6 +47,7 @@ static const struct option klp_diff_options[] = { > OPT_BOOLEAN('d', "debug", &debug, "enable all debug output"), > OPT_BOOLEAN(0, "debug-correlate", &debug_correlate, "enable correlation > debug output"), > OPT_BOOLEAN(0, "debug-clone", &debug_clone, "enable cloning debug > output"), > + OPT_STRING('s', "symvers", &symvers_path, "path", "path to > Module.symvers (default: Module.symvers)"), Could this cause a NULL pointer dereference if a user passes --no-symvers? Since OPT_STRING doesn't include the PARSE_OPT_NONEG flag, the option parsing machinery will automatically accept --no-symvers and set symvers_path to NULL. Later in read_exports(), this would result in calling fopen(NULL, "r"). > OPT_END(), > }; [ ... ] > @@ -85,16 +87,15 @@ static char *escape_str(const char *orig) > > static int read_exports(void) > { > - const char *symvers = "Module.symvers"; > char line[1024], *path = NULL; > unsigned int line_num = 1; > FILE *file; > > - file = fopen(symvers, "r"); > + file = fopen(symvers_path, "r"); > if (!file) { > - path = top_level_dir(symvers); > + path = top_level_dir(symvers_path); What happens here if the user supplies an absolute path like /build/out-of-tree/Module.symvers that fails the initial fopen()? It looks like top_level_dir() will unconditionally append the absolute path to the kernel root directory, resulting in a malformed path like /path/to/linux//build/out-of-tree/Module.symvers. Is it intentional to apply the top-level directory fallback to absolute paths? > if (!path) { > - ERROR("can't open '%s', \"objtool diff\" should be run > from the kernel tree", symvers); > + ERROR("can't open '%s', \"objtool diff\" should be run > from the kernel tree", symvers_path); Since the goal of this patch is to enable out-of-tree module patching, does this error message still make sense when a custom path is provided? It might be confusing to tell users they must run from the kernel tree when they explicitly passed an out-of-tree --symvers path. Additionally, if the fallback fopen() fails later on, the code calls ERROR_GLIBC("fopen") which prints "fopen: No such file or directory" without indicating which path failed. Would it be helpful to include the actual file path in these error diagnostics? [ ... ] -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=1
