From 568fb6f42ac6851320adaea25f8f1b94de14e40a Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Thu, 27 Sep 2018 17:17:57 +0000 Subject: kdb: print real address of pointers instead of hashed addresses Since commit ad67b74d2469 ("printk: hash addresses printed with %p"), all pointers printed with %p are printed with hashed addresses instead of real addresses in order to avoid leaking addresses in dmesg and syslog. But this applies to kdb too, with is unfortunate: Entering kdb (current=0x(ptrval), pid 329) due to Keyboard Entry kdb> ps 15 sleeping system daemon (state M) processes suppressed, use 'ps A' to see all. Task Addr Pid Parent [*] cpu State Thread Command 0x(ptrval) 329 328 1 0 R 0x(ptrval) *sh 0x(ptrval) 1 0 0 0 S 0x(ptrval) init 0x(ptrval) 3 2 0 0 D 0x(ptrval) rcu_gp 0x(ptrval) 4 2 0 0 D 0x(ptrval) rcu_par_gp 0x(ptrval) 5 2 0 0 D 0x(ptrval) kworker/0:0 0x(ptrval) 6 2 0 0 D 0x(ptrval) kworker/0:0H 0x(ptrval) 7 2 0 0 D 0x(ptrval) kworker/u2:0 0x(ptrval) 8 2 0 0 D 0x(ptrval) mm_percpu_wq 0x(ptrval) 10 2 0 0 D 0x(ptrval) rcu_preempt The whole purpose of kdb is to debug, and for debugging real addresses need to be known. In addition, data displayed by kdb doesn't go into dmesg. This patch replaces all %p by %px in kdb in order to display real addresses. Fixes: ad67b74d2469 ("printk: hash addresses printed with %p") Cc: Signed-off-by: Christophe Leroy Signed-off-by: Daniel Thompson --- kernel/debug/kdb/kdb_support.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'kernel/debug/kdb/kdb_support.c') diff --git a/kernel/debug/kdb/kdb_support.c b/kernel/debug/kdb/kdb_support.c index 990b3cc526c8..987eb73284d2 100644 --- a/kernel/debug/kdb/kdb_support.c +++ b/kernel/debug/kdb/kdb_support.c @@ -40,7 +40,7 @@ int kdbgetsymval(const char *symname, kdb_symtab_t *symtab) { if (KDB_DEBUG(AR)) - kdb_printf("kdbgetsymval: symname=%s, symtab=%p\n", symname, + kdb_printf("kdbgetsymval: symname=%s, symtab=%px\n", symname, symtab); memset(symtab, 0, sizeof(*symtab)); symtab->sym_start = kallsyms_lookup_name(symname); @@ -88,7 +88,7 @@ int kdbnearsym(unsigned long addr, kdb_symtab_t *symtab) char *knt1 = NULL; if (KDB_DEBUG(AR)) - kdb_printf("kdbnearsym: addr=0x%lx, symtab=%p\n", addr, symtab); + kdb_printf("kdbnearsym: addr=0x%lx, symtab=%px\n", addr, symtab); memset(symtab, 0, sizeof(*symtab)); if (addr < 4096) @@ -149,7 +149,7 @@ int kdbnearsym(unsigned long addr, kdb_symtab_t *symtab) symtab->mod_name = "kernel"; if (KDB_DEBUG(AR)) kdb_printf("kdbnearsym: returns %d symtab->sym_start=0x%lx, " - "symtab->mod_name=%p, symtab->sym_name=%p (%s)\n", ret, + "symtab->mod_name=%px, symtab->sym_name=%px (%s)\n", ret, symtab->sym_start, symtab->mod_name, symtab->sym_name, symtab->sym_name); @@ -887,13 +887,13 @@ void debug_kusage(void) __func__, dah_first); if (dah_first) { h_used = (struct debug_alloc_header *)debug_alloc_pool; - kdb_printf("%s: h_used %p size %d\n", __func__, h_used, + kdb_printf("%s: h_used %px size %d\n", __func__, h_used, h_used->size); } do { h_used = (struct debug_alloc_header *) ((char *)h_free + dah_overhead + h_free->size); - kdb_printf("%s: h_used %p size %d caller %p\n", + kdb_printf("%s: h_used %px size %d caller %px\n", __func__, h_used, h_used->size, h_used->caller); h_free = (struct debug_alloc_header *) (debug_alloc_pool + h_free->next); @@ -902,7 +902,7 @@ void debug_kusage(void) ((char *)h_free + dah_overhead + h_free->size); if ((char *)h_used - debug_alloc_pool != sizeof(debug_alloc_pool_aligned)) - kdb_printf("%s: h_used %p size %d caller %p\n", + kdb_printf("%s: h_used %px size %d caller %px\n", __func__, h_used, h_used->size, h_used->caller); out: spin_unlock(&dap_lock); -- cgit From c2b94c72d93d0929f48157eef128c4f9d2e603ce Mon Sep 17 00:00:00 2001 From: Prarit Bhargava Date: Thu, 20 Sep 2018 08:59:14 -0400 Subject: kdb: Use strscpy with destination buffer size MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit gcc 8.1.0 warns with: kernel/debug/kdb/kdb_support.c: In function ‘kallsyms_symbol_next’: kernel/debug/kdb/kdb_support.c:239:4: warning: ‘strncpy’ specified bound depends on the length of the source argument [-Wstringop-overflow=] strncpy(prefix_name, name, strlen(name)+1); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ kernel/debug/kdb/kdb_support.c:239:31: note: length computed here Use strscpy() with the destination buffer size, and use ellipses when displaying truncated symbols. v2: Use strscpy() Signed-off-by: Prarit Bhargava Cc: Jonathan Toppins Cc: Jason Wessel Cc: Daniel Thompson Cc: kgdb-bugreport@lists.sourceforge.net Reviewed-by: Daniel Thompson Signed-off-by: Daniel Thompson --- kernel/debug/kdb/kdb_io.c | 15 +++++++++------ kernel/debug/kdb/kdb_private.h | 2 +- kernel/debug/kdb/kdb_support.c | 10 +++++----- 3 files changed, 15 insertions(+), 12 deletions(-) (limited to 'kernel/debug/kdb/kdb_support.c') diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c index ed5d34925ad0..6a4b41484afe 100644 --- a/kernel/debug/kdb/kdb_io.c +++ b/kernel/debug/kdb/kdb_io.c @@ -216,7 +216,7 @@ static char *kdb_read(char *buffer, size_t bufsize) int count; int i; int diag, dtab_count; - int key; + int key, buf_size, ret; diag = kdbgetintenv("DTABCOUNT", &dtab_count); @@ -336,9 +336,8 @@ poll_again: else p_tmp = tmpbuffer; len = strlen(p_tmp); - count = kallsyms_symbol_complete(p_tmp, - sizeof(tmpbuffer) - - (p_tmp - tmpbuffer)); + buf_size = sizeof(tmpbuffer) - (p_tmp - tmpbuffer); + count = kallsyms_symbol_complete(p_tmp, buf_size); if (tab == 2 && count > 0) { kdb_printf("\n%d symbols are found.", count); if (count > dtab_count) { @@ -350,9 +349,13 @@ poll_again: } kdb_printf("\n"); for (i = 0; i < count; i++) { - if (WARN_ON(!kallsyms_symbol_next(p_tmp, i))) + ret = kallsyms_symbol_next(p_tmp, i, buf_size); + if (WARN_ON(!ret)) break; - kdb_printf("%s ", p_tmp); + if (ret != -E2BIG) + kdb_printf("%s ", p_tmp); + else + kdb_printf("%s... ", p_tmp); *(p_tmp + len) = '\0'; } if (i >= dtab_count) diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h index 1e5a502ba4a7..2118d8258b7c 100644 --- a/kernel/debug/kdb/kdb_private.h +++ b/kernel/debug/kdb/kdb_private.h @@ -83,7 +83,7 @@ typedef struct __ksymtab { unsigned long sym_start; unsigned long sym_end; } kdb_symtab_t; -extern int kallsyms_symbol_next(char *prefix_name, int flag); +extern int kallsyms_symbol_next(char *prefix_name, int flag, int buf_size); extern int kallsyms_symbol_complete(char *prefix_name, int max_len); /* Exported Symbols for kernel loadable modules to use. */ diff --git a/kernel/debug/kdb/kdb_support.c b/kernel/debug/kdb/kdb_support.c index 987eb73284d2..b14b0925c184 100644 --- a/kernel/debug/kdb/kdb_support.c +++ b/kernel/debug/kdb/kdb_support.c @@ -221,11 +221,13 @@ int kallsyms_symbol_complete(char *prefix_name, int max_len) * Parameters: * prefix_name prefix of a symbol name to lookup * flag 0 means search from the head, 1 means continue search. + * buf_size maximum length that can be written to prefix_name + * buffer * Returns: * 1 if a symbol matches the given prefix. * 0 if no string found */ -int kallsyms_symbol_next(char *prefix_name, int flag) +int kallsyms_symbol_next(char *prefix_name, int flag, int buf_size) { int prefix_len = strlen(prefix_name); static loff_t pos; @@ -235,10 +237,8 @@ int kallsyms_symbol_next(char *prefix_name, int flag) pos = 0; while ((name = kdb_walk_kallsyms(&pos))) { - if (strncmp(name, prefix_name, prefix_len) == 0) { - strncpy(prefix_name, name, strlen(name)+1); - return 1; - } + if (!strncmp(name, prefix_name, prefix_len)) + return strscpy(prefix_name, name, buf_size); } return 0; } -- cgit From 646558ff1643467d3b941b47f519867cbca462c3 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Sat, 4 Aug 2018 21:48:44 -0500 Subject: kdb: kdb_support: mark expected switch fall-throughs In preparation to enabling -Wimplicit-fallthrough, mark switch cases where we are expecting to fall through. Notice that in this particular case, I replaced the code comments with a proper "fall through" annotation, which is what GCC is expecting to find. Signed-off-by: Gustavo A. R. Silva Reviewed-by: Daniel Thompson Signed-off-by: Daniel Thompson --- kernel/debug/kdb/kdb_support.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel/debug/kdb/kdb_support.c') diff --git a/kernel/debug/kdb/kdb_support.c b/kernel/debug/kdb/kdb_support.c index b14b0925c184..50bf9b119bad 100644 --- a/kernel/debug/kdb/kdb_support.c +++ b/kernel/debug/kdb/kdb_support.c @@ -432,7 +432,7 @@ int kdb_getphysword(unsigned long *word, unsigned long addr, size_t size) *word = w8; break; } - /* drop through */ + /* fall through */ default: diag = KDB_BADWIDTH; kdb_printf("kdb_getphysword: bad width %ld\n", (long) size); @@ -481,7 +481,7 @@ int kdb_getword(unsigned long *word, unsigned long addr, size_t size) *word = w8; break; } - /* drop through */ + /* fall through */ default: diag = KDB_BADWIDTH; kdb_printf("kdb_getword: bad width %ld\n", (long) size); @@ -525,7 +525,7 @@ int kdb_putword(unsigned long addr, unsigned long word, size_t size) diag = kdb_putarea(addr, w8); break; } - /* drop through */ + /* fall through */ default: diag = KDB_BADWIDTH; kdb_printf("kdb_putword: bad width %ld\n", (long) size); -- cgit