[PATCH v4 tip/perf/core 3/4] uprobes: simplify find_active_uprobe_rcu() VMA checks

Andrii Nakryiko posted 4 patches 4 weeks ago
[PATCH v4 tip/perf/core 3/4] uprobes: simplify find_active_uprobe_rcu() VMA checks
Posted by Andrii Nakryiko 4 weeks ago
At the point where find_active_uprobe_rcu() is used we know that VMA in
question has triggered software breakpoint, so we don't need to validate
vma->vm_flags. Keep only vma->vm_file NULL check.

Acked-by: Oleg Nesterov <oleg@redhat.com>
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
 kernel/events/uprobes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 4ef4b51776eb..290c445768fa 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -2084,7 +2084,7 @@ static struct uprobe *find_active_uprobe_rcu(unsigned long bp_vaddr, int *is_swb
 	mmap_read_lock(mm);
 	vma = vma_lookup(mm, bp_vaddr);
 	if (vma) {
-		if (valid_vma(vma, false)) {
+		if (vma->vm_file) {
 			struct inode *inode = file_inode(vma->vm_file);
 			loff_t offset = vaddr_to_offset(vma, bp_vaddr);
 
-- 
2.43.5
Re: [PATCH v4 tip/perf/core 3/4] uprobes: simplify find_active_uprobe_rcu() VMA checks
Posted by Masami Hiramatsu (Google) 4 weeks ago
On Sun, 27 Oct 2024 18:08:17 -0700
Andrii Nakryiko <andrii@kernel.org> wrote:

> At the point where find_active_uprobe_rcu() is used we know that VMA in
> question has triggered software breakpoint, so we don't need to validate
> vma->vm_flags. Keep only vma->vm_file NULL check.
> 

Looks good to me.

Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Thanks,

> Acked-by: Oleg Nesterov <oleg@redhat.com>
> Suggested-by: Oleg Nesterov <oleg@redhat.com>
> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
> ---
>  kernel/events/uprobes.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> index 4ef4b51776eb..290c445768fa 100644
> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -2084,7 +2084,7 @@ static struct uprobe *find_active_uprobe_rcu(unsigned long bp_vaddr, int *is_swb
>  	mmap_read_lock(mm);
>  	vma = vma_lookup(mm, bp_vaddr);
>  	if (vma) {
> -		if (valid_vma(vma, false)) {
> +		if (vma->vm_file) {
>  			struct inode *inode = file_inode(vma->vm_file);
>  			loff_t offset = vaddr_to_offset(vma, bp_vaddr);
>  
> -- 
> 2.43.5
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>