From: Danilo Krummrich <dakr@kernel.org>
Date: Wed, 7 Jan 2026 10:35:00 +0000 (+0100)
Subject: rust: i2c: do not drop device private data on shutdown()
X-Git-Tag: v6.19-rc7~11^2~5
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4181aceb4af414bd6d2ce5eb9a22637bbb4f5f8c;p=thirdparty%2Fkernel%2Flinux.git

rust: i2c: do not drop device private data on shutdown()

We must not drop the device private data on shutdown(); none of the
registrations attached to devres that might access the device private
data are released before shutdown() is called.

Hence, freeing the device private data on shutdown() can cause UAF bugs.

Fixes: 57c5bd9aee94 ("rust: i2c: add basic I2C device and driver abstractions")
Acked-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Igor Korotin <igor.korotin.linux@gmail.com>
Link: https://patch.msgid.link/20260107103511.570525-2-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
---

diff --git a/rust/kernel/i2c.rs b/rust/kernel/i2c.rs
index 491e6cc25cf4..35b678b78d91 100644
--- a/rust/kernel/i2c.rs
+++ b/rust/kernel/i2c.rs
@@ -181,9 +181,9 @@ impl<T: Driver + 'static> Adapter<T> {
         // SAFETY: `shutdown_callback` is only ever called after a successful call to
         // `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called
         // and stored a `Pin<KBox<T>>`.
-        let data = unsafe { idev.as_ref().drvdata_obtain::<T>() };
+        let data = unsafe { idev.as_ref().drvdata_borrow::<T>() };
 
-        T::shutdown(idev, data.as_ref());
+        T::shutdown(idev, data);
     }
 
     /// The [`i2c::IdTable`] of the corresponding driver.