On Wed, 3 Jul 2024 11:25:35 -0700
Andrii Nakryiko [off-list ref] wrote:

On Wed, Jul 3, 2024 at 6:15 AM Masami Hiramatsu [off-list ref] wrote:

quoted

On Mon,  1 Jul 2024 15:39:25 -0700
Andrii Nakryiko [off-list ref] wrote:

quoted

It seems like uprobe_write_opcode() doesn't require writer locked
mmap_sem, any lock (reader or writer) should be sufficient. This was
established in a discussion in [0] and looking through existing code
seems to confirm that there is no need for write-locked mmap_sem.

Fix the comment to state this clearly.

  [0] https://lore.kernel.org/linux-trace-kernel/20240625190748.GC14254@redhat.com/ (local)

Fixes: 29dedee0e693 ("uprobes: Add mem_cgroup_charge_anon() into uprobe_write_opcode()")

nit: why this has Fixes but [01/12] doesn't?

Should I pick both to fixes branch?

I'd keep both of them in probes/for-next, tbh. They are not literally
fixing anything, just cleaning up comments. I can drop the Fixes tag
from this one, if you'd like.

Got it. Usually cleanup patch will not have Fixed tag, so if you don't mind,
please drop it.

Thank you,

quoted

Thank you,

quoted

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 081821fd529a..f87049c08ee9 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c

@@ -453,7 +453,7 @@ static int update_ref_ctr(struct uprobe *uprobe, struct mm_struct *mm,
  * @vaddr: the virtual address to store the opcode.
  * @opcode: opcode to be written at @vaddr.
  *
- * Called with mm->mmap_lock held for write.
+ * Called with mm->mmap_lock held for read or write.
  * Return 0 (success) or a negative errno.
  */
 int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
--

2.43.0

--
Masami Hiramatsu (Google) [off-list ref]

-- 
Masami Hiramatsu (Google) [off-list ref]