mirrors
/
linux-stable
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
1
0
Fork 0
Code Issues Releases Wiki Activity
linux-stable/drivers/nvdimm
History
Dan Williams 26f0ccbfde libnvdimm/dimm: Avoid race between probe and available_slots_show() 
commit 7018c897c2 upstream

Richard reports that the following test:

(while true; do
     cat /sys/bus/nd/devices/nmem*/available_slots 2>&1 > /dev/null
 done) &

while true; do
     for i in $(seq 0 4); do
         echo nmem$i > /sys/bus/nd/drivers/nvdimm/bind
     done
     for i in $(seq 0 4); do
         echo nmem$i > /sys/bus/nd/drivers/nvdimm/unbind
     done
 done

...fails with a crash signature like:

    divide error: 0000 [#1] SMP KASAN PTI
    RIP: 0010:nd_label_nfree+0x134/0x1a0 [libnvdimm]
    [..]
    Call Trace:
     available_slots_show+0x4e/0x120 [libnvdimm]
     dev_attr_show+0x42/0x80
     ? memset+0x20/0x40
     sysfs_kf_seq_show+0x218/0x410

The root cause is that available_slots_show() consults driver-data, but
fails to synchronize against device-unbind setting up a TOCTOU race to
access uninitialized memory.

Validate driver-data under the device-lock.

Fixes: 4d88a97aa9 ("libnvdimm, nvdimm: dimm driver and base libnvdimm device-driver infrastructure")
Cc: <stable@vger.kernel.org>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Coly Li <colyli@suse.com>
Reported-by: Richard Palethorpe <rpalethorpe@suse.com>
Acked-by: Richard Palethorpe <rpalethorpe@suse.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
[sudip: use device_lock()]
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 		2021-03-03 17:44:44 +01:00
..
Kconfig
…
Makefile
…
blk.c
…
btt.c libnvdimm/btt: Remove unnecessary code in btt_freelist_init 2020-05-27 16:42:00 +02:00
btt.h
…
btt_devs.c
…
bus.c
…
claim.c
…
core.c
…
dax_devs.c
…
dimm.c
…
dimm_devs.c libnvdimm/dimm: Avoid race between probe and available_slots_show() 2021-03-03 17:44:44 +01:00
e820.c
…
label.c
…
label.h
…
namespace_devs.c
…
nd-core.h
…
nd.h block: Move SECTOR_SIZE and SECTOR_SHIFT definitions into <linux/blkdev.h> 2020-09-12 11:47:36 +02:00
pfn.h
…
pfn_devs.c
…
pmem.c
…
pmem.h
…
region.c
…
region_devs.c
…