From 9c24624727f6d6c460e45762a408ca5f5b9b8ef2 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Tue, 9 Dec 2008 13:14:27 -0800 Subject: [PATCH] KSYM_SYMBOL_LEN fixes Miles Lane tailing /sys files hit a BUG which Pekka Enberg has tracked to my 966c8c12dc9e77f931e2281ba25d2f0244b06949 sprint_symbol(): use less stack exposing a bug in slub's list_locations() - kallsyms_lookup() writes a 0 to namebuf[KSYM_NAME_LEN-1], but that was beyond the end of page provided. The 100 slop which list_locations() allows at end of page looks roughly enough for all the other stuff it might print after the symbol before it checks again: break out KSYM_SYMBOL_LEN earlier than before. Latencytop and ftrace and are using KSYM_NAME_LEN buffers where they need KSYM_SYMBOL_LEN buffers, and vmallocinfo a 2*KSYM_NAME_LEN buffer where it wants a KSYM_SYMBOL_LEN buffer: fix those before anyone copies them. [akpm@linux-foundation.org: ftrace.h needs module.h] Signed-off-by: Hugh Dickins Cc: Christoph Lameter Cc Miles Lane Acked-by: Pekka Enberg Acked-by: Steven Rostedt Acked-by: Frederic Weisbecker Cc: Rusty Russell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/proc/base.c | 2 +- include/linux/ftrace.h | 3 ++- kernel/latencytop.c | 2 +- mm/slub.c | 2 +- mm/vmalloc.c | 2 +- 5 files changed, 6 insertions(+), 5 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 486cf3fe713..d4677603c88 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -371,7 +371,7 @@ static int lstats_show_proc(struct seq_file *m, void *v) task->latency_record[i].time, task->latency_record[i].max); for (q = 0; q < LT_BACKTRACEDEPTH; q++) { - char sym[KSYM_NAME_LEN]; + char sym[KSYM_SYMBOL_LEN]; char *c; if (!task->latency_record[i].backtrace[q]) break; diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 703eb53cfa2..9c5bc6be2b0 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -6,6 +6,7 @@ #include #include #include +#include #include #ifdef CONFIG_FUNCTION_TRACER @@ -231,7 +232,7 @@ ftrace_init_module(unsigned long *start, unsigned long *end) { } struct boot_trace { pid_t caller; - char func[KSYM_NAME_LEN]; + char func[KSYM_SYMBOL_LEN]; int result; unsigned long long duration; /* usecs */ ktime_t calltime; diff --git a/kernel/latencytop.c b/kernel/latencytop.c index 5e7b45c5692..449db466bdb 100644 --- a/kernel/latencytop.c +++ b/kernel/latencytop.c @@ -191,7 +191,7 @@ static int lstats_show(struct seq_file *m, void *v) latency_record[i].time, latency_record[i].max); for (q = 0; q < LT_BACKTRACEDEPTH; q++) { - char sym[KSYM_NAME_LEN]; + char sym[KSYM_SYMBOL_LEN]; char *c; if (!latency_record[i].backtrace[q]) break; diff --git a/mm/slub.c b/mm/slub.c index 749588a50a5..a2cd47d89e0 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3597,7 +3597,7 @@ static int list_locations(struct kmem_cache *s, char *buf, for (i = 0; i < t.count; i++) { struct location *l = &t.loc[i]; - if (len > PAGE_SIZE - 100) + if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100) break; len += sprintf(buf + len, "%7ld ", l->count); diff --git a/mm/vmalloc.c b/mm/vmalloc.c index f3f6e075856..1ddb77ba399 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1717,7 +1717,7 @@ static int s_show(struct seq_file *m, void *p) v->addr, v->addr + v->size, v->size); if (v->caller) { - char buff[2 * KSYM_NAME_LEN]; + char buff[KSYM_SYMBOL_LEN]; seq_putc(m, ' '); sprint_symbol(buff, (unsigned long)v->caller); -- 2.41.1