From 37252db6aa576c34fd794a5a54fb32d7a8b3a07a Mon Sep 17 00:00:00 2001 From: Jiri Kosina Date: Wed, 26 Oct 2011 13:10:39 +1030 Subject: [PATCH 1/2] kmod: prevent kmod_loop_msg overflow in __request_module() Due to post-increment in condition of kmod_loop_msg in __request_module(), the system log can be spammed by much more than 5 instances of the 'runaway loop' message if the number of events triggering it makes the kmod_loop_msg to overflow. Fix that by making sure we never increment it past the threshold. Signed-off-by: Jiri Kosina Signed-off-by: Rusty Russell CC: stable@kernel.org --- kernel/kmod.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/kmod.c b/kernel/kmod.c index ddc7644c1305..a4bea97c75b6 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -114,10 +114,12 @@ int __request_module(bool wait, const char *fmt, ...) atomic_inc(&kmod_concurrent); if (atomic_read(&kmod_concurrent) > max_modprobes) { /* We may be blaming an innocent here, but unlikely */ - if (kmod_loop_msg++ < 5) + if (kmod_loop_msg < 5) { printk(KERN_ERR "request_module: runaway loop modprobe %s\n", module_name); + kmod_loop_msg++; + } atomic_dec(&kmod_concurrent); return -ENOMEM; } From b1e4d20cbf2ef8e27515da032b95fdcbb5b06bf1 Mon Sep 17 00:00:00 2001 From: Michal Schmidt Date: Mon, 10 Oct 2011 00:03:37 +0200 Subject: [PATCH 2/2] params: make dashes and underscores in parameter names truly equal The user may use "foo-bar" for a kernel parameter defined as "foo_bar". Make sure it works the other way around too. Apply the equality of dashes and underscores on early_params and __setup params as well. The example given in Documentation/kernel-parameters.txt indicates that this is the intended behaviour. With the patch the kernel accepts "log-buf-len=1M" as expected. https://bugzilla.redhat.com/show_bug.cgi?id=744545 Signed-off-by: Michal Schmidt Signed-off-by: Rusty Russell (neatened implementations) --- include/linux/moduleparam.h | 20 ++++++++++++++++++++ init/main.c | 4 ++-- kernel/params.c | 21 ++++++++++++++------- 3 files changed, 36 insertions(+), 9 deletions(-) diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h index ddaae98c53f9..fffb10bd5514 100644 --- a/include/linux/moduleparam.h +++ b/include/linux/moduleparam.h @@ -262,6 +262,26 @@ static inline void __kernel_param_unlock(void) .str = &__param_string_##name, 0, perm); \ __MODULE_PARM_TYPE(name, "string") +/** + * parameq - checks if two parameter names match + * @name1: parameter name 1 + * @name2: parameter name 2 + * + * Returns true if the two parameter names are equal. + * Dashes (-) are considered equal to underscores (_). + */ +extern bool parameq(const char *name1, const char *name2); + +/** + * parameqn - checks if two parameter names match + * @name1: parameter name 1 + * @name2: parameter name 2 + * @n: the length to compare + * + * Similar to parameq(), except it compares @n characters. + */ +extern bool parameqn(const char *name1, const char *name2, size_t n); + /* Called on module insert or kernel boot */ extern int parse_args(const char *name, char *args, diff --git a/init/main.c b/init/main.c index 03b408dff825..63f5f6f8dc3b 100644 --- a/init/main.c +++ b/init/main.c @@ -163,7 +163,7 @@ static int __init obsolete_checksetup(char *line) p = __setup_start; do { int n = strlen(p->str); - if (!strncmp(line, p->str, n)) { + if (parameqn(line, p->str, n)) { if (p->early) { /* Already done in parse_early_param? * (Needs exact match on param part). @@ -392,7 +392,7 @@ static int __init do_early_param(char *param, char *val) const struct obs_kernel_param *p; for (p = __setup_start; p < __setup_end; p++) { - if ((p->early && strcmp(param, p->str) == 0) || + if ((p->early && parameq(param, p->str)) || (strcmp(param, "console") == 0 && strcmp(p->str, "earlycon") == 0) ) { diff --git a/kernel/params.c b/kernel/params.c index 22df3e0d142a..821788947e40 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -67,20 +67,27 @@ static void maybe_kfree_parameter(void *param) } } -static inline char dash2underscore(char c) +static char dash2underscore(char c) { if (c == '-') return '_'; return c; } -static inline int parameq(const char *input, const char *paramname) +bool parameqn(const char *a, const char *b, size_t n) { - unsigned int i; - for (i = 0; dash2underscore(input[i]) == paramname[i]; i++) - if (input[i] == '\0') - return 1; - return 0; + size_t i; + + for (i = 0; i < n; i++) { + if (dash2underscore(a[i]) != dash2underscore(b[i])) + return false; + } + return true; +} + +bool parameq(const char *a, const char *b) +{ + return parameqn(a, b, strlen(a)+1); } static int parse_one(char *param,