On Mon, 1 Jul 2024 15:39:25 -0700 Andrii Nakryiko <andrii@xxxxxxxxxx> wrote: > 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@xxxxxxxxxx/ > > 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? Thank you, > Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx> > --- > 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) <mhiramat@xxxxxxxxxx>
