From: Alexandra Winter wintera@linux.ibm.com

mainline inclusion from mainline-v5.15-rc3 commit d2b59bd4b06d84a4eadb520b0f71c62fe8ec0a62 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9R4P3 CVE: CVE-2021-47382

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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Commit 0b9902c1fcc5 ("s390/qeth: fix deadlock during recovery") removed taking discipline_mutex inside qeth_do_reset(), fixing potential deadlocks. An error path was missed though, that still takes discipline_mutex and thus has the original deadlock potential.

Intermittent deadlocks were seen when a qeth channel path is configured offline, causing a race between qeth_do_reset and ccwgroup_remove. Call qeth_set_offline() directly in the qeth_do_reset() error case and then a new variant of ccwgroup_set_offline(), without taking discipline_mutex.

Fixes: b41b554c1ee7 ("s390/qeth: fix locking for discipline setup / removal") Signed-off-by: Alexandra Winter wintera@linux.ibm.com Reviewed-by: Julian Wiedmann jwi@linux.ibm.com Signed-off-by: Julian Wiedmann jwi@linux.ibm.com Signed-off-by: Jakub Kicinski kuba@kernel.org

Conflicts: arch/s390/include/asm/ccwgroup.h [Fix context] Signed-off-by: Yuan Can yuancan@huawei.com --- arch/s390/include/asm/ccwgroup.h | 2 +- drivers/s390/cio/ccwgroup.c | 10 ++++++++-- drivers/s390/net/qeth_core_main.c | 3 ++- 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/arch/s390/include/asm/ccwgroup.h b/arch/s390/include/asm/ccwgroup.h index ad3acb1e882b..8a22da9a735a 100644 --- a/arch/s390/include/asm/ccwgroup.h +++ b/arch/s390/include/asm/ccwgroup.h @@ -58,7 +58,7 @@ struct ccwgroup_device *get_ccwgroupdev_by_busid(struct ccwgroup_driver *gdrv, char *bus_id);

extern int ccwgroup_set_online(struct ccwgroup_device *gdev); -extern int ccwgroup_set_offline(struct ccwgroup_device *gdev); +int ccwgroup_set_offline(struct ccwgroup_device *gdev, bool call_gdrv);

extern int ccwgroup_probe_ccwdev(struct ccw_device *cdev); extern void ccwgroup_remove_ccwdev(struct ccw_device *cdev); diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c index 483a9ecfcbb1..cfdc1c7825d0 100644 --- a/drivers/s390/cio/ccwgroup.c +++ b/drivers/s390/cio/ccwgroup.c @@ -98,12 +98,13 @@ EXPORT_SYMBOL(ccwgroup_set_online); /** * ccwgroup_set_offline() - disable a ccwgroup device * @gdev: target ccwgroup device + * @call_gdrv: Call the registered gdrv set_offline function * * This function attempts to put the ccwgroup device into the offline state. * Returns: * %0 on success and a negative error value on failure. */ -int ccwgroup_set_offline(struct ccwgroup_device *gdev) +int ccwgroup_set_offline(struct ccwgroup_device *gdev, bool call_gdrv) { struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver); int ret = -EINVAL; @@ -112,11 +113,16 @@ int ccwgroup_set_offline(struct ccwgroup_device *gdev) return -EAGAIN; if (gdev->state == CCWGROUP_OFFLINE) goto out; + if (!call_gdrv) { + ret = 0; + goto offline; + } if (gdrv->set_offline) ret = gdrv->set_offline(gdev); if (ret) goto out;

+offline: gdev->state = CCWGROUP_OFFLINE; out: atomic_set(&gdev->onoff, 0); @@ -145,7 +151,7 @@ static ssize_t ccwgroup_online_store(struct device *dev, if (value == 1) ret = ccwgroup_set_online(gdev); else if (value == 0) - ret = ccwgroup_set_offline(gdev); + ret = ccwgroup_set_offline(gdev, true); else ret = -EINVAL; out: diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c index b164dc574b46..7356fe8b3990 100644 --- a/drivers/s390/net/qeth_core_main.c +++ b/drivers/s390/net/qeth_core_main.c @@ -5398,7 +5398,8 @@ static int qeth_do_reset(void *data) dev_info(&card->gdev->dev, "Device successfully recovered!\n"); } else { - ccwgroup_set_offline(card->gdev); + qeth_set_offline(card, disc, true); + ccwgroup_set_offline(card->gdev, false); dev_warn(&card->gdev->dev, "The qeth device driver failed to recover an error on the device\n"); }