From 93964fd4ea6ab86a2d2853a9ae56ae0c24cbbe16 Mon Sep 17 00:00:00 2001 From: James Bottomley Date: Mon, 31 Jul 2017 15:49:54 +0200 Subject: [PATCH] parisc: pdc_stable: Fix locking when creating sysfs links There's no need to take the write lock when creating sysfs links. This patch fixes the following BUG: BUG: sleeping function called from invalid context at mm/slab.h:416 in_atomic(): 1, irqs_disabled(): 0, pid: 1, name: swapper/0 CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.13.0-rc2-00110-g0b5477d9dabd #111 Backtrace: [<0000000040217ac8>] show_stack+0x20/0x38 [<00000000406fbbb0>] dump_stack+0xb0/0x128 [<0000000040274090>] ___might_sleep+0x180/0x1b8 [<0000000040274144>] __might_sleep+0x7c/0xe8 [<0000000040373874>] kmem_cache_alloc+0x14c/0x1e0 [<0000000040419514>] __kernfs_new_node+0x84/0x1b8 [<000000004041b09c>] kernfs_new_node+0x3c/0x78 [<000000004041e040>] kernfs_create_link+0x40/0xd8 [<000000004041f320>] sysfs_do_create_link_sd.isra.0+0xb0/0x130 [<000000004041f3d4>] sysfs_create_link+0x34/0x58 [<000000004011b4a4>] pdc_stable_init+0x2c4/0x458 [<0000000040200250>] do_one_initcall+0x70/0x1d8 [<0000000040101644>] kernel_init_freeable+0x27c/0x390 [<000000004020be44>] kernel_init+0x24/0x1c0 Signed-off-by: James Bottomley Reported-by: Meelis Roos Signed-off-by: Helge Deller --- drivers/parisc/pdc_stable.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/parisc/pdc_stable.c b/drivers/parisc/pdc_stable.c index 7147aa53e9a2..b1ff46fe4547 100644 --- a/drivers/parisc/pdc_stable.c +++ b/drivers/parisc/pdc_stable.c @@ -333,11 +333,11 @@ pdcspath_hwpath_write(struct pdcspath_entry *entry, const char *buf, size_t coun /* Update the symlink to the real device */ sysfs_remove_link(&entry->kobj, "device"); + write_unlock(&entry->rw_lock); + ret = sysfs_create_link(&entry->kobj, &entry->dev->kobj, "device"); WARN_ON(ret); - write_unlock(&entry->rw_lock); - printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" path to \"%s\"\n", entry->name, buf); @@ -998,6 +998,7 @@ pdcs_register_pathentries(void) /* kobject is now registered */ write_lock(&entry->rw_lock); entry->ready = 2; + write_unlock(&entry->rw_lock); /* Add a nice symlink to the real device */ if (entry->dev) { @@ -1005,7 +1006,6 @@ pdcs_register_pathentries(void) WARN_ON(err); } - write_unlock(&entry->rw_lock); kobject_uevent(&entry->kobj, KOBJ_ADD); } -- GitLab