Thread (10 messages) 10 messages, 4 authors, 27d ago

Re: PowerPC: Random memory corruption causing kernel oops on Power11

From: Paul Moore <paul@paul-moore.com>
Date: 2026-05-29 18:25:01
Also in: lkml, selinux

On Fri, May 29, 2026 at 12:11 PM Stephen Smalley
[off-list ref] wrote:
On Fri, May 29, 2026 at 11:39 AM Paul Moore [off-list ref] wrote:
quoted
On Fri, May 29, 2026 at 11:19 AM Stephen Smalley
[off-list ref] wrote:
quoted
Alternatively, I suppose we could just update the dentry_path_raw()
call to also pass PATH_MAX, but
I don't see why we want to use __getname/__putname() instead of just
direct kmalloc/kfree here so
the size of the buffer is immediately evident to the reader.
It's reverted, see the posting below:

https://lore.kernel.org/selinux/20260529153608.30853-2-paul@paul-moore.com (local)

I think there is still value in using __getname()/__putname() here as
opposed to a simple kmalloc()/kfree() pairing, but either way we need
to adjust the buffer length in selinux_genfs_get_sid() accordingly to
use PATH_MAX instead of PAGE_SIZE.
IIUC, __getname()/__putname() were originally internal helpers for
getname()/putname() and allocated from names_cachep for struct
filename. commit c3a3577cdb35 ("struct filename: use names_cachep only
for getname() and friends") switched __getname()/__putname() over to
just generic kmalloc/kfree so that other users of those helpers would
stop allocating from names_cachep and noted that those lingering users
could be converted to explicit kmalloc() over time. So I don't think
vfs folks want new users of __getname()/__putname() but I could be
wrong.
Whoever wants to submit a patch to do the conversion again should
chase that down.

-- 
paul-moore.com
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