From efeb156e7275c5b6c6e0f96aceb3c6abf98fc392 Mon Sep 17 00:00:00 2001 From: Stephen Boyd Date: Thu, 12 Jan 2012 17:17:11 -0800 Subject: kprobes: silence DEBUG_STRICT_USER_COPY_CHECKS=y warning Enabling DEBUG_STRICT_USER_COPY_CHECKS causes the following warning: In file included from arch/x86/include/asm/uaccess.h:573, from kernel/kprobes.c:55: In function 'copy_from_user', inlined from 'write_enabled_file_bool' at kernel/kprobes.c:2191: arch/x86/include/asm/uaccess_64.h:65: warning: call to 'copy_from_user_overflow' declared with attribute warning: copy_from_user() buffer size is not provably correct presumably due to buf_size being signed causing GCC to fail to see that buf_size can't become negative. Signed-off-by: Stephen Boyd Cc: Ananth N Mavinakayanahalli Cc: Anil S Keshavamurthy Cc: David S. Miller Acked-by: Masami Hiramatsu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kprobes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/kprobes.c') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index e5d84644823b..95dd7212e610 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2198,7 +2198,7 @@ static ssize_t write_enabled_file_bool(struct file *file, const char __user *user_buf, size_t count, loff_t *ppos) { char buf[32]; - int buf_size; + size_t buf_size; buf_size = min(count, (sizeof(buf)-1)); if (copy_from_user(buf, user_buf, buf_size)) -- cgit v1.2.3 From d496aab567e7e52b3e974c9192a5de6e77dce32c Mon Sep 17 00:00:00 2001 From: Ananth N Mavinakayanahalli Date: Fri, 20 Jan 2012 14:34:04 -0800 Subject: kprobes: initialize before using a hlist Commit ef53d9c5e ("kprobes: improve kretprobe scalability with hashed locking") introduced a bug where we can potentially leak kretprobe_instances since we initialize a hlist head after having used it. Initialize the hlist head before using it. Reported by: Jim Keniston Acked-by: Jim Keniston Signed-off-by: Ananth N Mavinakayanahalli Acked-by: Masami Hiramatsu Cc: Srinivasa D S Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kprobes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/kprobes.c') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 95dd7212e610..29f5b65bee29 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1077,6 +1077,7 @@ void __kprobes kprobe_flush_task(struct task_struct *tk) /* Early boot. kretprobe_table_locks not yet initialized. */ return; + INIT_HLIST_HEAD(&empty_rp); hash = hash_ptr(tk, KPROBE_HASH_BITS); head = &kretprobe_inst_table[hash]; kretprobe_table_lock(hash, &flags); @@ -1085,7 +1086,6 @@ void __kprobes kprobe_flush_task(struct task_struct *tk) recycle_rp_inst(ri, &empty_rp); } kretprobe_table_unlock(hash, &flags); - INIT_HLIST_HEAD(&empty_rp); hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { hlist_del(&ri->hlist); kfree(ri); -- cgit v1.2.3 From 55ca6140e9bb307efc97a9301a4f501de02a6fd6 Mon Sep 17 00:00:00 2001 From: Jiang Liu Date: Fri, 3 Feb 2012 15:37:16 -0800 Subject: kprobes: fix a memory leak in function pre_handler_kretprobe() In function pre_handler_kretprobe(), the allocated kretprobe_instance object will get leaked if the entry_handler callback returns non-zero. This may cause all the preallocated kretprobe_instance objects exhausted. This issue can be reproduced by changing samples/kprobes/kretprobe_example.c to probe "mutex_unlock". And the fix is straightforward: just put the allocated kretprobe_instance object back onto the free_instances list. [akpm@linux-foundation.org: use raw_spin_lock/unlock] Signed-off-by: Jiang Liu Acked-by: Jim Keniston Acked-by: Ananth N Mavinakayanahalli Cc: Masami Hiramatsu Cc: Anil S Keshavamurthy Cc: "David S. Miller" Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kprobes.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'kernel/kprobes.c') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 29f5b65bee29..9788c0ec6f43 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1673,8 +1673,12 @@ static int __kprobes pre_handler_kretprobe(struct kprobe *p, ri->rp = rp; ri->task = current; - if (rp->entry_handler && rp->entry_handler(ri, regs)) + if (rp->entry_handler && rp->entry_handler(ri, regs)) { + raw_spin_lock_irqsave(&rp->lock, flags); + hlist_add_head(&ri->hlist, &rp->free_instances); + raw_spin_unlock_irqrestore(&rp->lock, flags); return 0; + } arch_prepare_kretprobe(ri, regs); -- cgit v1.2.3