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Subject[PATCH AUTOSEL 5.2 13/44] nvme-core: Fix extra device_put() call on error path
Date
From: Logan Gunthorpe <logang@deltatee.com>

[ Upstream commit 8c36e66fb407ce076535a7db98ab9f6d720b866a ]

In the error path for nvme_init_subsystem(), nvme_put_subsystem()
will call device_put(), but it will get called again after the
mutex_unlock().

The device_put() only needs to be called if device_add() fails.

This bug caused a KASAN use-after-free error when adding and
removing subsytems in a loop:

BUG: KASAN: use-after-free in device_del+0x8d9/0x9a0
Read of size 8 at addr ffff8883cdaf7120 by task multipathd/329

CPU: 0 PID: 329 Comm: multipathd Not tainted 5.2.0-rc6-vmlocalyes-00019-g70a2b39005fd-dirty #314
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
Call Trace:
dump_stack+0x7b/0xb5
print_address_description+0x6f/0x280
? device_del+0x8d9/0x9a0
__kasan_report+0x148/0x199
? device_del+0x8d9/0x9a0
? class_release+0x100/0x130
? device_del+0x8d9/0x9a0
kasan_report+0x12/0x20
__asan_report_load8_noabort+0x14/0x20
device_del+0x8d9/0x9a0
? device_platform_notify+0x70/0x70
nvme_destroy_subsystem+0xf9/0x150
nvme_free_ctrl+0x280/0x3a0
device_release+0x72/0x1d0
kobject_put+0x144/0x410
put_device+0x13/0x20
nvme_free_ns+0xc4/0x100
nvme_release+0xb3/0xe0
__blkdev_put+0x549/0x6e0
? kasan_check_write+0x14/0x20
? bd_set_size+0xb0/0xb0
? kasan_check_write+0x14/0x20
? mutex_lock+0x8f/0xe0
? __mutex_lock_slowpath+0x20/0x20
? locks_remove_file+0x239/0x370
blkdev_put+0x72/0x2c0
blkdev_close+0x8d/0xd0
__fput+0x256/0x770
? _raw_read_lock_irq+0x40/0x40
____fput+0xe/0x10
task_work_run+0x10c/0x180
? filp_close+0xf7/0x140
exit_to_usermode_loop+0x151/0x170
do_syscall_64+0x240/0x2e0
? prepare_exit_to_usermode+0xd5/0x190
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f5a79af05d7
Code: 00 00 0f 05 48 3d 00 f0 ff ff 77 3f c3 66 0f 1f 44 00 00 53 89 fb 48 83 ec 10 e8 c4 fb ff ff 89 df 89 c2 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 2b 89 d7 89 44 24 0c e8 06 fc ff ff 8b 44 24
RSP: 002b:00007f5a7799c810 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000008 RCX: 00007f5a79af05d7
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000008
RBP: 00007f5a58000f98 R08: 0000000000000002 R09: 00007f5a7935ee80
R10: 0000000000000000 R11: 0000000000000293 R12: 000055e432447240
R13: 0000000000000000 R14: 0000000000000001 R15: 000055e4324a9cf0

Allocated by task 1236:
save_stack+0x21/0x80
__kasan_kmalloc.constprop.6+0xab/0xe0
kasan_kmalloc+0x9/0x10
kmem_cache_alloc_trace+0x102/0x210
nvme_init_identify+0x13c3/0x3820
nvme_loop_configure_admin_queue+0x4fa/0x5e0
nvme_loop_create_ctrl+0x469/0xf40
nvmf_dev_write+0x19a3/0x21ab
__vfs_write+0x66/0x120
vfs_write+0x154/0x490
ksys_write+0x104/0x240
__x64_sys_write+0x73/0xb0
do_syscall_64+0xa5/0x2e0
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 329:
save_stack+0x21/0x80
__kasan_slab_free+0x129/0x190
kasan_slab_free+0xe/0x10
kfree+0xa7/0x200
nvme_release_subsystem+0x49/0x60
device_release+0x72/0x1d0
kobject_put+0x144/0x410
put_device+0x13/0x20
klist_class_dev_put+0x31/0x40
klist_put+0x8f/0xf0
klist_del+0xe/0x10
device_del+0x3a7/0x9a0
nvme_destroy_subsystem+0xf9/0x150
nvme_free_ctrl+0x280/0x3a0
device_release+0x72/0x1d0
kobject_put+0x144/0x410
put_device+0x13/0x20
nvme_free_ns+0xc4/0x100
nvme_release+0xb3/0xe0
__blkdev_put+0x549/0x6e0
blkdev_put+0x72/0x2c0
blkdev_close+0x8d/0xd0
__fput+0x256/0x770
____fput+0xe/0x10
task_work_run+0x10c/0x180
exit_to_usermode_loop+0x151/0x170
do_syscall_64+0x240/0x2e0
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: 32fd90c40768 ("nvme: change locking for the per-subsystem controller list")
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by : Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/nvme/host/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index ab1a2b1ec3637..dfbd5872f4422 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2440,6 +2440,7 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
if (ret) {
dev_err(ctrl->device,
"failed to register subsystem device.\n");
+ put_device(&subsys->dev);
goto out_unlock;
}
ida_init(&subsys->ns_ida);
@@ -2462,7 +2463,6 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
nvme_put_subsystem(subsys);
out_unlock:
mutex_unlock(&nvme_subsystems_lock);
- put_device(&subsys->dev);
return ret;
}

--
2.20.1
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