Benjamin Bara (2): i2c: core: Run atomic i2c xfer when !preemptible i2c: core: Fix atomic xfer check for non-preempt config
drivers/i2c/i2c-core.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
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From: Benjamin Bara benjamin.bara@skidata.com
stable inclusion from stable-v5.10.202 commit 25284c46b657f48c0f3880a2e0706c70d81182c0 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9RFEQ CVE: CVE-2023-52791
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit aa49c90894d06e18a1ee7c095edbd2f37c232d02 upstream.
Since bae1d3a05a8b, i2c transfers are non-atomic if preemption is disabled. However, non-atomic i2c transfers require preemption (e.g. in wait_for_completion() while waiting for the DMA).
panic() calls preempt_disable_notrace() before calling emergency_restart(). Therefore, if an i2c device is used for the restart, the xfer should be atomic. This avoids warnings like:
[ 12.667612] WARNING: CPU: 1 PID: 1 at kernel/rcu/tree_plugin.h:318 rcu_note_context_switch+0x33c/0x6b0 [ 12.676926] Voluntary context switch within RCU read-side critical section! ... [ 12.742376] schedule_timeout from wait_for_completion_timeout+0x90/0x114 [ 12.749179] wait_for_completion_timeout from tegra_i2c_wait_completion+0x40/0x70 ... [ 12.994527] atomic_notifier_call_chain from machine_restart+0x34/0x58 [ 13.001050] machine_restart from panic+0x2a8/0x32c
Use !preemptible() instead, which is basically the same check as pre-v5.2.
Fixes: bae1d3a05a8b ("i2c: core: remove use of in_atomic()") Cc: stable@vger.kernel.org # v5.2+ Suggested-by: Dmitry Osipenko dmitry.osipenko@collabora.com Acked-by: Wolfram Sang wsa@kernel.org Reviewed-by: Dmitry Osipenko dmitry.osipenko@collabora.com Tested-by: Nishanth Menon nm@ti.com Signed-off-by: Benjamin Bara benjamin.bara@skidata.com Link: https://lore.kernel.org/r/20230327-tegra-pmic-reboot-v7-2-18699d5dcd76@skida... Signed-off-by: Lee Jones lee@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Kaixiong Yu yukaixiong@huawei.com --- drivers/i2c/i2c-core.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/i2c/i2c-core.h b/drivers/i2c/i2c-core.h index 8ce261167a2d..ea17f13b44c8 100644 --- a/drivers/i2c/i2c-core.h +++ b/drivers/i2c/i2c-core.h @@ -29,7 +29,7 @@ int i2c_dev_irq_from_resources(const struct resource *resources, */ static inline bool i2c_in_atomic_xfer_mode(void) { - return system_state > SYSTEM_RUNNING && irqs_disabled(); + return system_state > SYSTEM_RUNNING && !preemptible(); }
static inline int __i2c_lock_bus_helper(struct i2c_adapter *adap)
From: Benjamin Bara benjamin.bara@skidata.com
stable inclusion from stable-v5.10.208 commit 4aca0af44721fbbbf619fddca6c41ff84fbf2170 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9RFEQ CVE: CVE-2023-52791
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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Since commit aa49c90894d0 ("i2c: core: Run atomic i2c xfer when !preemptible"), the whole reboot/power off sequence on non-preempt kernels is using atomic i2c xfer, as !preemptible() always results to 1.
During device_shutdown(), the i2c might be used a lot and not all busses have implemented an atomic xfer handler. This results in a lot of avoidable noise, like:
[ 12.687169] No atomic I2C transfer handler for 'i2c-0' [ 12.692313] WARNING: CPU: 6 PID: 275 at drivers/i2c/i2c-core.h:40 i2c_smbus_xfer+0x100/0x118 ...
Fix this by allowing non-atomic xfer when the interrupts are enabled, as it was before.
Link: https://lore.kernel.org/r/20231222230106.73f030a5@yea Link: https://lore.kernel.org/r/20240102150350.3180741-1-mwalle@kernel.org Link: https://lore.kernel.org/linux-i2c/13271b9b-4132-46ef-abf8-2c311967bb46@mailb... Fixes: aa49c90894d0 ("i2c: core: Run atomic i2c xfer when !preemptible") Cc: stable@vger.kernel.org # v5.2+ Signed-off-by: Benjamin Bara benjamin.bara@skidata.com Tested-by: Michael Walle mwalle@kernel.org Tested-by: Tor Vic torvic9@mailbox.org [wsa: removed a comment which needs more work, code is ok] Signed-off-by: Wolfram Sang wsa@kernel.org Signed-off-by: Kaixiong Yu yukaixiong@huawei.com --- drivers/i2c/i2c-core.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/i2c-core.h b/drivers/i2c/i2c-core.h index ea17f13b44c8..ec28024a646d 100644 --- a/drivers/i2c/i2c-core.h +++ b/drivers/i2c/i2c-core.h @@ -3,6 +3,7 @@ * i2c-core.h - interfaces internal to the I2C framework */
+#include <linux/kconfig.h> #include <linux/rwsem.h>
struct i2c_devinfo { @@ -29,7 +30,8 @@ int i2c_dev_irq_from_resources(const struct resource *resources, */ static inline bool i2c_in_atomic_xfer_mode(void) { - return system_state > SYSTEM_RUNNING && !preemptible(); + return system_state > SYSTEM_RUNNING && + (IS_ENABLED(CONFIG_PREEMPT_COUNT) ? !preemptible() : irqs_disabled()); }
static inline int __i2c_lock_bus_helper(struct i2c_adapter *adap)
-
Kaixiong Yu -
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