From 6268d7da4d192af339f4d688942b9ccb45a65e04 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Fri, 18 Dec 2020 18:41:41 -0800 Subject: [PATCH 1/1] device-dax: Fix range release There are multiple locations that open-code the release of the last range in a device-dax instance. Consolidate this into a new dev_dax_trim_range() helper. This also addresses a kmemleak report: # cat /sys/kernel/debug/kmemleak [..] unreferenced object 0xffff976bd46f6240 (size 64): comm "ndctl", pid 23556, jiffies 4299514316 (age 5406.733s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 20 c3 37 00 00 00 .......... .7... ff ff ff 7f 38 00 00 00 00 00 00 00 00 00 00 00 ....8........... backtrace: [<00000000064003cf>] __kmalloc_track_caller+0x136/0x379 [<00000000d85e3c52>] krealloc+0x67/0x92 [<00000000d7d3ba8a>] __alloc_dev_dax_range+0x73/0x25c [<0000000027d58626>] devm_create_dev_dax+0x27d/0x416 [<00000000434abd43>] __dax_pmem_probe+0x1c9/0x1000 [dax_pmem_core] [<0000000083726c1c>] dax_pmem_probe+0x10/0x1f [dax_pmem] [<00000000b5f2319c>] nvdimm_bus_probe+0x9d/0x340 [libnvdimm] [<00000000c055e544>] really_probe+0x230/0x48d [<000000006cabd38e>] driver_probe_device+0x122/0x13b [<0000000029c7b95a>] device_driver_attach+0x5b/0x60 [<0000000053e5659b>] bind_store+0xb7/0xc3 [<00000000d3bdaadc>] drv_attr_store+0x27/0x31 [<00000000949069c5>] sysfs_kf_write+0x4a/0x57 [<000000004a8b5adf>] kernfs_fop_write+0x150/0x1e5 [<00000000bded60f0>] __vfs_write+0x1b/0x34 [<00000000b92900f0>] vfs_write+0xd8/0x1d1 Reported-by: Jane Chu Cc: Zhen Lei Link: https://lore.kernel.org/r/160834570161.1791850.14911670304441510419.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams --- drivers/dax/bus.c | 44 +++++++++++++++++++++----------------------- 1 file changed, 21 insertions(+), 23 deletions(-) diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c index 9761cb40d4bb..720cd140209f 100644 --- a/drivers/dax/bus.c +++ b/drivers/dax/bus.c @@ -367,19 +367,28 @@ void kill_dev_dax(struct dev_dax *dev_dax) } EXPORT_SYMBOL_GPL(kill_dev_dax); -static void free_dev_dax_ranges(struct dev_dax *dev_dax) +static void trim_dev_dax_range(struct dev_dax *dev_dax) { + int i = dev_dax->nr_range - 1; + struct range *range = &dev_dax->ranges[i].range; struct dax_region *dax_region = dev_dax->region; - int i; device_lock_assert(dax_region->dev); - for (i = 0; i < dev_dax->nr_range; i++) { - struct range *range = &dev_dax->ranges[i].range; - - __release_region(&dax_region->res, range->start, - range_len(range)); + dev_dbg(&dev_dax->dev, "delete range[%d]: %#llx:%#llx\n", i, + (unsigned long long)range->start, + (unsigned long long)range->end); + + __release_region(&dax_region->res, range->start, range_len(range)); + if (--dev_dax->nr_range == 0) { + kfree(dev_dax->ranges); + dev_dax->ranges = NULL; } - dev_dax->nr_range = 0; +} + +static void free_dev_dax_ranges(struct dev_dax *dev_dax) +{ + while (dev_dax->nr_range) + trim_dev_dax_range(dev_dax); } static void unregister_dev_dax(void *dev) @@ -804,15 +813,10 @@ static int alloc_dev_dax_range(struct dev_dax *dev_dax, u64 start, return 0; rc = devm_register_dax_mapping(dev_dax, dev_dax->nr_range - 1); - if (rc) { - dev_dbg(dev, "delete range[%d]: %pa:%pa\n", dev_dax->nr_range - 1, - &alloc->start, &alloc->end); - dev_dax->nr_range--; - __release_region(res, alloc->start, resource_size(alloc)); - return rc; - } + if (rc) + trim_dev_dax_range(dev_dax); - return 0; + return rc; } static int adjust_dev_dax_range(struct dev_dax *dev_dax, struct resource *res, resource_size_t size) @@ -885,12 +889,7 @@ static int dev_dax_shrink(struct dev_dax *dev_dax, resource_size_t size) if (shrink >= range_len(range)) { devm_release_action(dax_region->dev, unregister_dax_mapping, &mapping->dev); - __release_region(&dax_region->res, range->start, - range_len(range)); - dev_dax->nr_range--; - dev_dbg(dev, "delete range[%d]: %#llx:%#llx\n", i, - (unsigned long long) range->start, - (unsigned long long) range->end); + trim_dev_dax_range(dev_dax); to_shrink -= shrink; if (!to_shrink) break; @@ -1267,7 +1266,6 @@ static void dev_dax_release(struct device *dev) put_dax(dax_dev); free_dev_dax_id(dev_dax); dax_region_put(dax_region); - kfree(dev_dax->ranges); kfree(dev_dax->pgmap); kfree(dev_dax); } -- 2.20.1