* [PATCH v2] driver core: fix use-after-free of driver_override via driver_match_device() @ 2025-11-26 16:00 Gui-Dong Han 2025-11-27 9:16 ` Greg KH 0 siblings, 1 reply; 6+ messages in thread From: Gui-Dong Han @ 2025-11-26 16:00 UTC (permalink / raw) To: gregkh, rafael, dakr Cc: linux-kernel, baijiaju1990, Gui-Dong Han, Qiu-ji Chen driver_set_override() modifies and frees dev->driver_override while holding device_lock(dev). However, driver_match_device() reads dev->driver_override when calling bus match functions. Currently, driver_match_device() is called from three sites. One site (__device_attach_driver) holds device_lock(dev), but the other two (bind_store and __driver_attach) do not. This allows a concurrent driver_set_override() to free the string while driver_match_device() is using it, leading to a use-after-free (UAF). This issue affects at least 11 bus types (including PCI, AMBA, Platform) that rely on driver_override for matching. Fix this by holding device_lock(dev) around the driver_match_device() calls in bind_store() and __driver_attach(). This ensures all access to dev->driver_override via driver_match_device() is protected by the device lock. Also add a lock assertion to driver_match_device() to prevent future locking regressions. Tested with the PoCs from Bugzilla that trigger this UAF. Stress testing the two newly locked paths for 24 hours with CONFIG_PROVE_LOCKING and CONFIG_LOCKDEP enabled showed no UAF recurrence and no lockdep warnings. Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220789 Suggested-by: Qiu-ji Chen <chenqiuji666@gmail.com> Signed-off-by: Gui-Dong Han <hanguidong02@gmail.com> --- v2: * Add device_lock_assert() in driver_match_device() to enforce locking requirement, as suggested by Greg KH. v1: * The Bugzilla entry contains full KASAN reports and two PoCs that reliably reproduce the UAF on both unlocked paths using a standard QEMU setup (default e1000 device at 0000:00:03.0). I chose to fix this in the driver core for the following reasons: 1. Both racing functions are part of the driver core. 2. Fixing this per-driver/per-bus is tedious and would require careful ad-hoc locking that does not align with the existing device_lock(dev). 3. We cannot simply add device_lock(dev) inside bus match functions because one call path (__device_attach_driver) already holds this lock. Adding the lock inside the match callback would cause a deadlock on that path. --- drivers/base/base.h | 2 ++ drivers/base/bus.c | 17 ++++++++++++----- drivers/base/dd.c | 3 +++ 3 files changed, 17 insertions(+), 5 deletions(-) diff --git a/drivers/base/base.h b/drivers/base/base.h index 86fa7fbb3548..011e910a53f8 100644 --- a/drivers/base/base.h +++ b/drivers/base/base.h @@ -166,6 +166,8 @@ void device_set_deferred_probe_reason(const struct device *dev, struct va_format static inline int driver_match_device(const struct device_driver *drv, struct device *dev) { + /* Protects against driver_set_override() races */ + device_lock_assert(dev); return drv->bus->match ? drv->bus->match(dev, drv) : 1; } diff --git a/drivers/base/bus.c b/drivers/base/bus.c index 5e75e1bce551..9e62d6009058 100644 --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -261,13 +261,20 @@ static ssize_t bind_store(struct device_driver *drv, const char *buf, const struct bus_type *bus = bus_get(drv->bus); struct device *dev; int err = -ENODEV; + int ret; dev = bus_find_device_by_name(bus, NULL, buf); - if (dev && driver_match_device(drv, dev)) { - err = device_driver_attach(drv, dev); - if (!err) { - /* success */ - err = count; + if (dev) { + /* Protects against driver_set_override() races */ + device_lock(dev); + ret = driver_match_device(drv, dev); + device_unlock(dev); + if (ret) { + err = device_driver_attach(drv, dev); + if (!err) { + /* success */ + err = count; + } } } put_device(dev); diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 13ab98e033ea..db60b4500136 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -1170,7 +1170,10 @@ static int __driver_attach(struct device *dev, void *data) * is an error. */ + /* Protects against driver_set_override() races */ + device_lock(dev); ret = driver_match_device(drv, dev); + device_unlock(dev); if (ret == 0) { /* no match */ return 0; -- 2.43.0 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v2] driver core: fix use-after-free of driver_override via driver_match_device() 2025-11-26 16:00 [PATCH v2] driver core: fix use-after-free of driver_override via driver_match_device() Gui-Dong Han @ 2025-11-27 9:16 ` Greg KH 2025-11-27 15:00 ` Gui-Dong Han 0 siblings, 1 reply; 6+ messages in thread From: Greg KH @ 2025-11-27 9:16 UTC (permalink / raw) To: Gui-Dong Han; +Cc: rafael, dakr, linux-kernel, baijiaju1990, Qiu-ji Chen On Thu, Nov 27, 2025 at 12:00:11AM +0800, Gui-Dong Han wrote: > driver_set_override() modifies and frees dev->driver_override while > holding device_lock(dev). However, driver_match_device() reads > dev->driver_override when calling bus match functions. > > Currently, driver_match_device() is called from three sites. One site > (__device_attach_driver) holds device_lock(dev), but the other two > (bind_store and __driver_attach) do not. This allows a concurrent > driver_set_override() to free the string while driver_match_device() is > using it, leading to a use-after-free (UAF). > > This issue affects at least 11 bus types (including PCI, AMBA, Platform) > that rely on driver_override for matching. > > Fix this by holding device_lock(dev) around the driver_match_device() calls > in bind_store() and __driver_attach(). This ensures all access to > dev->driver_override via driver_match_device() is protected by the device > lock. Also add a lock assertion to driver_match_device() to prevent future > locking regressions. > > Tested with the PoCs from Bugzilla that trigger this UAF. Stress testing > the two newly locked paths for 24 hours with CONFIG_PROVE_LOCKING and > CONFIG_LOCKDEP enabled showed no UAF recurrence and no lockdep > warnings. > > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220789 > Suggested-by: Qiu-ji Chen <chenqiuji666@gmail.com> > Signed-off-by: Gui-Dong Han <hanguidong02@gmail.com> > --- > v2: > * Add device_lock_assert() in driver_match_device() to enforce locking > requirement, as suggested by Greg KH. > v1: > * The Bugzilla entry contains full KASAN reports and two PoCs that reliably > reproduce the UAF on both unlocked paths using a standard QEMU setup > (default e1000 device at 0000:00:03.0). > I chose to fix this in the driver core for the following reasons: > 1. Both racing functions are part of the driver core. > 2. Fixing this per-driver/per-bus is tedious and would require careful > ad-hoc locking that does not align with the existing device_lock(dev). > 3. We cannot simply add device_lock(dev) inside bus match functions because > one call path (__device_attach_driver) already holds this lock. Adding the > lock inside the match callback would cause a deadlock on that path. > --- > drivers/base/base.h | 2 ++ > drivers/base/bus.c | 17 ++++++++++++----- > drivers/base/dd.c | 3 +++ > 3 files changed, 17 insertions(+), 5 deletions(-) > > diff --git a/drivers/base/base.h b/drivers/base/base.h > index 86fa7fbb3548..011e910a53f8 100644 > --- a/drivers/base/base.h > +++ b/drivers/base/base.h > @@ -166,6 +166,8 @@ void device_set_deferred_probe_reason(const struct device *dev, struct va_format > static inline int driver_match_device(const struct device_driver *drv, > struct device *dev) > { > + /* Protects against driver_set_override() races */ > + device_lock_assert(dev); > return drv->bus->match ? drv->bus->match(dev, drv) : 1; A new line after the assert? And thanks for adding the comment, but: > } > > diff --git a/drivers/base/bus.c b/drivers/base/bus.c > index 5e75e1bce551..9e62d6009058 100644 > --- a/drivers/base/bus.c > +++ b/drivers/base/bus.c > @@ -261,13 +261,20 @@ static ssize_t bind_store(struct device_driver *drv, const char *buf, > const struct bus_type *bus = bus_get(drv->bus); > struct device *dev; > int err = -ENODEV; > + int ret; > > dev = bus_find_device_by_name(bus, NULL, buf); > - if (dev && driver_match_device(drv, dev)) { > - err = device_driver_attach(drv, dev); > - if (!err) { > - /* success */ > - err = count; > + if (dev) { > + /* Protects against driver_set_override() races */ This comment isn't needed anymore. > + device_lock(dev); > + ret = driver_match_device(drv, dev); > + device_unlock(dev); > + if (ret) { > + err = device_driver_attach(drv, dev); > + if (!err) { > + /* success */ > + err = count; > + } > } > } > put_device(dev); > diff --git a/drivers/base/dd.c b/drivers/base/dd.c > index 13ab98e033ea..db60b4500136 100644 > --- a/drivers/base/dd.c > +++ b/drivers/base/dd.c > @@ -1170,7 +1170,10 @@ static int __driver_attach(struct device *dev, void *data) > * is an error. > */ > > + /* Protects against driver_set_override() races */ Nor is this one. Also, I looked again, and why are you not grabbing the lock in the bind_store() sysfs call? driver_match_device() is only called in 3 places, 2 now have the lock held, and one does not. This feels wrong. thanks, greg k-h ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2] driver core: fix use-after-free of driver_override via driver_match_device() 2025-11-27 9:16 ` Greg KH @ 2025-11-27 15:00 ` Gui-Dong Han 2025-11-27 15:21 ` Greg KH 0 siblings, 1 reply; 6+ messages in thread From: Gui-Dong Han @ 2025-11-27 15:00 UTC (permalink / raw) To: Greg KH; +Cc: rafael, dakr, linux-kernel, baijiaju1990, Qiu-ji Chen On Thu, Nov 27, 2025 at 5:16 PM Greg KH <gregkh@linuxfoundation.org> wrote: > > On Thu, Nov 27, 2025 at 12:00:11AM +0800, Gui-Dong Han wrote: > > driver_set_override() modifies and frees dev->driver_override while > > holding device_lock(dev). However, driver_match_device() reads > > dev->driver_override when calling bus match functions. > > > > Currently, driver_match_device() is called from three sites. One site > > (__device_attach_driver) holds device_lock(dev), but the other two > > (bind_store and __driver_attach) do not. This allows a concurrent > > driver_set_override() to free the string while driver_match_device() is > > using it, leading to a use-after-free (UAF). > > > > This issue affects at least 11 bus types (including PCI, AMBA, Platform) > > that rely on driver_override for matching. > > > > Fix this by holding device_lock(dev) around the driver_match_device() calls > > in bind_store() and __driver_attach(). This ensures all access to > > dev->driver_override via driver_match_device() is protected by the device > > lock. Also add a lock assertion to driver_match_device() to prevent future > > locking regressions. > > > > Tested with the PoCs from Bugzilla that trigger this UAF. Stress testing > > the two newly locked paths for 24 hours with CONFIG_PROVE_LOCKING and > > CONFIG_LOCKDEP enabled showed no UAF recurrence and no lockdep > > warnings. > > > > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220789 > > Suggested-by: Qiu-ji Chen <chenqiuji666@gmail.com> > > Signed-off-by: Gui-Dong Han <hanguidong02@gmail.com> > > --- > > v2: > > * Add device_lock_assert() in driver_match_device() to enforce locking > > requirement, as suggested by Greg KH. > > v1: > > * The Bugzilla entry contains full KASAN reports and two PoCs that reliably > > reproduce the UAF on both unlocked paths using a standard QEMU setup > > (default e1000 device at 0000:00:03.0). > > I chose to fix this in the driver core for the following reasons: > > 1. Both racing functions are part of the driver core. > > 2. Fixing this per-driver/per-bus is tedious and would require careful > > ad-hoc locking that does not align with the existing device_lock(dev). > > 3. We cannot simply add device_lock(dev) inside bus match functions because > > one call path (__device_attach_driver) already holds this lock. Adding the > > lock inside the match callback would cause a deadlock on that path. > > --- > > drivers/base/base.h | 2 ++ > > drivers/base/bus.c | 17 ++++++++++++----- > > drivers/base/dd.c | 3 +++ > > 3 files changed, 17 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/base/base.h b/drivers/base/base.h > > index 86fa7fbb3548..011e910a53f8 100644 > > --- a/drivers/base/base.h > > +++ b/drivers/base/base.h > > @@ -166,6 +166,8 @@ void device_set_deferred_probe_reason(const struct device *dev, struct va_format > > static inline int driver_match_device(const struct device_driver *drv, > > struct device *dev) > > { > > + /* Protects against driver_set_override() races */ > > + device_lock_assert(dev); > > return drv->bus->match ? drv->bus->match(dev, drv) : 1; > > A new line after the assert? > > And thanks for adding the comment, but: > > > } > > > > diff --git a/drivers/base/bus.c b/drivers/base/bus.c > > index 5e75e1bce551..9e62d6009058 100644 > > --- a/drivers/base/bus.c > > +++ b/drivers/base/bus.c > > @@ -261,13 +261,20 @@ static ssize_t bind_store(struct device_driver *drv, const char *buf, > > const struct bus_type *bus = bus_get(drv->bus); > > struct device *dev; > > int err = -ENODEV; > > + int ret; > > > > dev = bus_find_device_by_name(bus, NULL, buf); > > - if (dev && driver_match_device(drv, dev)) { > > - err = device_driver_attach(drv, dev); > > - if (!err) { > > - /* success */ > > - err = count; > > + if (dev) { > > + /* Protects against driver_set_override() races */ > > This comment isn't needed anymore. > > > + device_lock(dev); > > + ret = driver_match_device(drv, dev); > > + device_unlock(dev); > > + if (ret) { > > + err = device_driver_attach(drv, dev); > > + if (!err) { > > + /* success */ > > + err = count; > > + } > > } > > } > > put_device(dev); > > diff --git a/drivers/base/dd.c b/drivers/base/dd.c > > index 13ab98e033ea..db60b4500136 100644 > > --- a/drivers/base/dd.c > > +++ b/drivers/base/dd.c > > @@ -1170,7 +1170,10 @@ static int __driver_attach(struct device *dev, void *data) > > * is an error. > > */ > > > > + /* Protects against driver_set_override() races */ > > Nor is this one. > > Also, I looked again, and why are you not grabbing the lock in the > bind_store() sysfs call? driver_match_device() is only called in 3 > places, 2 now have the lock held, and one does not. This feels wrong. Actually, the change in drivers/base/bus.c is exactly for the bind_store() path. So all 3 call sites are covered and locked with this patch. I have verified this with the PoC for bind_store(), and the new lockdep assertion does not trigger any warnings, confirming the lock is properly held. I have just sent a v3 patch which adds the blank line and removes the redundant comments as suggested. Thanks, Gui-Dong Han ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2] driver core: fix use-after-free of driver_override via driver_match_device() 2025-11-27 15:00 ` Gui-Dong Han @ 2025-11-27 15:21 ` Greg KH 2026-01-13 2:27 ` Gui-Dong Han 0 siblings, 1 reply; 6+ messages in thread From: Greg KH @ 2025-11-27 15:21 UTC (permalink / raw) To: Gui-Dong Han; +Cc: rafael, dakr, linux-kernel, baijiaju1990, Qiu-ji Chen On Thu, Nov 27, 2025 at 11:00:16PM +0800, Gui-Dong Han wrote: > On Thu, Nov 27, 2025 at 5:16 PM Greg KH <gregkh@linuxfoundation.org> wrote: > > > > On Thu, Nov 27, 2025 at 12:00:11AM +0800, Gui-Dong Han wrote: > > > driver_set_override() modifies and frees dev->driver_override while > > > holding device_lock(dev). However, driver_match_device() reads > > > dev->driver_override when calling bus match functions. > > > > > > Currently, driver_match_device() is called from three sites. One site > > > (__device_attach_driver) holds device_lock(dev), but the other two > > > (bind_store and __driver_attach) do not. This allows a concurrent > > > driver_set_override() to free the string while driver_match_device() is > > > using it, leading to a use-after-free (UAF). > > > > > > This issue affects at least 11 bus types (including PCI, AMBA, Platform) > > > that rely on driver_override for matching. > > > > > > Fix this by holding device_lock(dev) around the driver_match_device() calls > > > in bind_store() and __driver_attach(). This ensures all access to > > > dev->driver_override via driver_match_device() is protected by the device > > > lock. Also add a lock assertion to driver_match_device() to prevent future > > > locking regressions. > > > > > > Tested with the PoCs from Bugzilla that trigger this UAF. Stress testing > > > the two newly locked paths for 24 hours with CONFIG_PROVE_LOCKING and > > > CONFIG_LOCKDEP enabled showed no UAF recurrence and no lockdep > > > warnings. > > > > > > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220789 > > > Suggested-by: Qiu-ji Chen <chenqiuji666@gmail.com> > > > Signed-off-by: Gui-Dong Han <hanguidong02@gmail.com> > > > --- > > > v2: > > > * Add device_lock_assert() in driver_match_device() to enforce locking > > > requirement, as suggested by Greg KH. > > > v1: > > > * The Bugzilla entry contains full KASAN reports and two PoCs that reliably > > > reproduce the UAF on both unlocked paths using a standard QEMU setup > > > (default e1000 device at 0000:00:03.0). > > > I chose to fix this in the driver core for the following reasons: > > > 1. Both racing functions are part of the driver core. > > > 2. Fixing this per-driver/per-bus is tedious and would require careful > > > ad-hoc locking that does not align with the existing device_lock(dev). > > > 3. We cannot simply add device_lock(dev) inside bus match functions because > > > one call path (__device_attach_driver) already holds this lock. Adding the > > > lock inside the match callback would cause a deadlock on that path. > > > --- > > > drivers/base/base.h | 2 ++ > > > drivers/base/bus.c | 17 ++++++++++++----- > > > drivers/base/dd.c | 3 +++ > > > 3 files changed, 17 insertions(+), 5 deletions(-) > > > > > > diff --git a/drivers/base/base.h b/drivers/base/base.h > > > index 86fa7fbb3548..011e910a53f8 100644 > > > --- a/drivers/base/base.h > > > +++ b/drivers/base/base.h > > > @@ -166,6 +166,8 @@ void device_set_deferred_probe_reason(const struct device *dev, struct va_format > > > static inline int driver_match_device(const struct device_driver *drv, > > > struct device *dev) > > > { > > > + /* Protects against driver_set_override() races */ > > > + device_lock_assert(dev); > > > return drv->bus->match ? drv->bus->match(dev, drv) : 1; > > > > A new line after the assert? > > > > And thanks for adding the comment, but: > > > > > } > > > > > > diff --git a/drivers/base/bus.c b/drivers/base/bus.c > > > index 5e75e1bce551..9e62d6009058 100644 > > > --- a/drivers/base/bus.c > > > +++ b/drivers/base/bus.c > > > @@ -261,13 +261,20 @@ static ssize_t bind_store(struct device_driver *drv, const char *buf, > > > const struct bus_type *bus = bus_get(drv->bus); > > > struct device *dev; > > > int err = -ENODEV; > > > + int ret; > > > > > > dev = bus_find_device_by_name(bus, NULL, buf); > > > - if (dev && driver_match_device(drv, dev)) { > > > - err = device_driver_attach(drv, dev); > > > - if (!err) { > > > - /* success */ > > > - err = count; > > > + if (dev) { > > > + /* Protects against driver_set_override() races */ > > > > This comment isn't needed anymore. > > > > > + device_lock(dev); > > > + ret = driver_match_device(drv, dev); > > > + device_unlock(dev); > > > + if (ret) { > > > + err = device_driver_attach(drv, dev); > > > + if (!err) { > > > + /* success */ > > > + err = count; > > > + } > > > } > > > } > > > put_device(dev); > > > diff --git a/drivers/base/dd.c b/drivers/base/dd.c > > > index 13ab98e033ea..db60b4500136 100644 > > > --- a/drivers/base/dd.c > > > +++ b/drivers/base/dd.c > > > @@ -1170,7 +1170,10 @@ static int __driver_attach(struct device *dev, void *data) > > > * is an error. > > > */ > > > > > > + /* Protects against driver_set_override() races */ > > > > Nor is this one. > > > > Also, I looked again, and why are you not grabbing the lock in the > > bind_store() sysfs call? driver_match_device() is only called in 3 > > places, 2 now have the lock held, and one does not. This feels wrong. > > Actually, the change in drivers/base/bus.c is exactly for the > bind_store() path. So all 3 call sites are covered and locked with > this patch. Ugh, nevermind, your patch changes bind_store() I missed that, my fault :( > I have verified this with the PoC for bind_store(), and the new > lockdep assertion does not trigger any warnings, confirming the lock > is properly held. Makes sense, thanks! I'll queue up your patch after 6.19-rc1 is out, thanks! greg k-h ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2] driver core: fix use-after-free of driver_override via driver_match_device() 2025-11-27 15:21 ` Greg KH @ 2026-01-13 2:27 ` Gui-Dong Han 2026-01-13 9:58 ` Danilo Krummrich 0 siblings, 1 reply; 6+ messages in thread From: Gui-Dong Han @ 2026-01-13 2:27 UTC (permalink / raw) To: Greg KH; +Cc: rafael, dakr, linux-kernel, baijiaju1990, Qiu-ji Chen On Thu, Nov 27, 2025 at 11:21 PM Greg KH <gregkh@linuxfoundation.org> wrote: > > On Thu, Nov 27, 2025 at 11:00:16PM +0800, Gui-Dong Han wrote: > > On Thu, Nov 27, 2025 at 5:16 PM Greg KH <gregkh@linuxfoundation.org> wrote: > > > > > > On Thu, Nov 27, 2025 at 12:00:11AM +0800, Gui-Dong Han wrote: > > > > driver_set_override() modifies and frees dev->driver_override while > > > > holding device_lock(dev). However, driver_match_device() reads > > > > dev->driver_override when calling bus match functions. > > > > > > > > Currently, driver_match_device() is called from three sites. One site > > > > (__device_attach_driver) holds device_lock(dev), but the other two > > > > (bind_store and __driver_attach) do not. This allows a concurrent > > > > driver_set_override() to free the string while driver_match_device() is > > > > using it, leading to a use-after-free (UAF). > > > > > > > > This issue affects at least 11 bus types (including PCI, AMBA, Platform) > > > > that rely on driver_override for matching. > > > > > > > > Fix this by holding device_lock(dev) around the driver_match_device() calls > > > > in bind_store() and __driver_attach(). This ensures all access to > > > > dev->driver_override via driver_match_device() is protected by the device > > > > lock. Also add a lock assertion to driver_match_device() to prevent future > > > > locking regressions. > > > > > > > > Tested with the PoCs from Bugzilla that trigger this UAF. Stress testing > > > > the two newly locked paths for 24 hours with CONFIG_PROVE_LOCKING and > > > > CONFIG_LOCKDEP enabled showed no UAF recurrence and no lockdep > > > > warnings. > > > > > > > > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220789 > > > > Suggested-by: Qiu-ji Chen <chenqiuji666@gmail.com> > > > > Signed-off-by: Gui-Dong Han <hanguidong02@gmail.com> > > > > --- > > > > v2: > > > > * Add device_lock_assert() in driver_match_device() to enforce locking > > > > requirement, as suggested by Greg KH. > > > > v1: > > > > * The Bugzilla entry contains full KASAN reports and two PoCs that reliably > > > > reproduce the UAF on both unlocked paths using a standard QEMU setup > > > > (default e1000 device at 0000:00:03.0). > > > > I chose to fix this in the driver core for the following reasons: > > > > 1. Both racing functions are part of the driver core. > > > > 2. Fixing this per-driver/per-bus is tedious and would require careful > > > > ad-hoc locking that does not align with the existing device_lock(dev). > > > > 3. We cannot simply add device_lock(dev) inside bus match functions because > > > > one call path (__device_attach_driver) already holds this lock. Adding the > > > > lock inside the match callback would cause a deadlock on that path. > > > > --- > > > > drivers/base/base.h | 2 ++ > > > > drivers/base/bus.c | 17 ++++++++++++----- > > > > drivers/base/dd.c | 3 +++ > > > > 3 files changed, 17 insertions(+), 5 deletions(-) > > > > > > > > diff --git a/drivers/base/base.h b/drivers/base/base.h > > > > index 86fa7fbb3548..011e910a53f8 100644 > > > > --- a/drivers/base/base.h > > > > +++ b/drivers/base/base.h > > > > @@ -166,6 +166,8 @@ void device_set_deferred_probe_reason(const struct device *dev, struct va_format > > > > static inline int driver_match_device(const struct device_driver *drv, > > > > struct device *dev) > > > > { > > > > + /* Protects against driver_set_override() races */ > > > > + device_lock_assert(dev); > > > > return drv->bus->match ? drv->bus->match(dev, drv) : 1; > > > > > > A new line after the assert? > > > > > > And thanks for adding the comment, but: > > > > > > > } > > > > > > > > diff --git a/drivers/base/bus.c b/drivers/base/bus.c > > > > index 5e75e1bce551..9e62d6009058 100644 > > > > --- a/drivers/base/bus.c > > > > +++ b/drivers/base/bus.c > > > > @@ -261,13 +261,20 @@ static ssize_t bind_store(struct device_driver *drv, const char *buf, > > > > const struct bus_type *bus = bus_get(drv->bus); > > > > struct device *dev; > > > > int err = -ENODEV; > > > > + int ret; > > > > > > > > dev = bus_find_device_by_name(bus, NULL, buf); > > > > - if (dev && driver_match_device(drv, dev)) { > > > > - err = device_driver_attach(drv, dev); > > > > - if (!err) { > > > > - /* success */ > > > > - err = count; > > > > + if (dev) { > > > > + /* Protects against driver_set_override() races */ > > > > > > This comment isn't needed anymore. > > > > > > > + device_lock(dev); > > > > + ret = driver_match_device(drv, dev); > > > > + device_unlock(dev); > > > > + if (ret) { > > > > + err = device_driver_attach(drv, dev); > > > > + if (!err) { > > > > + /* success */ > > > > + err = count; > > > > + } > > > > } > > > > } > > > > put_device(dev); > > > > diff --git a/drivers/base/dd.c b/drivers/base/dd.c > > > > index 13ab98e033ea..db60b4500136 100644 > > > > --- a/drivers/base/dd.c > > > > +++ b/drivers/base/dd.c > > > > @@ -1170,7 +1170,10 @@ static int __driver_attach(struct device *dev, void *data) > > > > * is an error. > > > > */ > > > > > > > > + /* Protects against driver_set_override() races */ > > > > > > Nor is this one. > > > > > > Also, I looked again, and why are you not grabbing the lock in the > > > bind_store() sysfs call? driver_match_device() is only called in 3 > > > places, 2 now have the lock held, and one does not. This feels wrong. > > > > Actually, the change in drivers/base/bus.c is exactly for the > > bind_store() path. So all 3 call sites are covered and locked with > > this patch. > > Ugh, nevermind, your patch changes bind_store() I missed that, my fault > :( > > > I have verified this with the PoC for bind_store(), and the new > > lockdep assertion does not trigger any warnings, confirming the lock > > is properly held. > > Makes sense, thanks! > > I'll queue up your patch after 6.19-rc1 is out, thanks! Hi Greg, Apologies for the ping, but I noticed this patch hasn't been merged yet and I couldn't find it in the driver-core-next branch. I wanted to check if it might have been missed. If you plan to pick it up, please use v3 which I sent shortly after this thread to address your feedback regarding code formatting. v3 link: https://lore.kernel.org/all/20251127145753.13080-1-hanguidong02@gmail.com/ Sorry if I missed something on my end. Thanks. ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2] driver core: fix use-after-free of driver_override via driver_match_device() 2026-01-13 2:27 ` Gui-Dong Han @ 2026-01-13 9:58 ` Danilo Krummrich 0 siblings, 0 replies; 6+ messages in thread From: Danilo Krummrich @ 2026-01-13 9:58 UTC (permalink / raw) To: Gui-Dong Han Cc: Greg KH, rafael, linux-kernel, baijiaju1990, Qiu-ji Chen, 2045gemini On Tue Jan 13, 2026 at 3:27 AM CET, Gui-Dong Han wrote: > If you plan to pick it up, please use v3 which I sent shortly after > this thread to address your feedback regarding code formatting. Sorry for being late on this (I was travelling in Nov / Dec), I just replied to v3. > v3 link: https://lore.kernel.org/all/20251127145753.13080-1-hanguidong02@gmail.com/ ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2026-01-13 9:58 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2025-11-26 16:00 [PATCH v2] driver core: fix use-after-free of driver_override via driver_match_device() Gui-Dong Han 2025-11-27 9:16 ` Greg KH 2025-11-27 15:00 ` Gui-Dong Han 2025-11-27 15:21 ` Greg KH 2026-01-13 2:27 ` Gui-Dong Han 2026-01-13 9:58 ` Danilo Krummrich
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