diff options
| author | Dan Williams <dan.j.williams@intel.com> | 2022-02-17 03:25:11 +0300 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2022-02-18 03:51:13 +0300 |
| commit | 74be98774dfbc5b8b795db726bd772e735d2edd4 (patch) | |
| tree | 4e2dd92b77d4c312cce779a7e4a6c19783c4cc25 /drivers/cxl | |
| parent | 41ae9105f5e23e98a1734be2eeddddf488e42c2e (diff) | |
| download | linux-74be98774dfbc5b8b795db726bd772e735d2edd4.tar.xz | |
cxl/port: Hold port reference until decoder release
KASAN + DEBUG_KOBJECT_RELEASE reports a potential use-after-free in
cxl_decoder_release() where it goes to reference its parent, a cxl_port,
to free its id back to port->decoder_ida.
BUG: KASAN: use-after-free in to_cxl_port+0x18/0x90 [cxl_core]
Read of size 8 at addr ffff888119270908 by task kworker/35:2/379
CPU: 35 PID: 379 Comm: kworker/35:2 Tainted: G OE 5.17.0-rc2+ #198
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
Workqueue: events kobject_delayed_cleanup
Call Trace:
<TASK>
dump_stack_lvl+0x59/0x73
print_address_description.constprop.0+0x1f/0x150
? to_cxl_port+0x18/0x90 [cxl_core]
kasan_report.cold+0x83/0xdf
? to_cxl_port+0x18/0x90 [cxl_core]
to_cxl_port+0x18/0x90 [cxl_core]
cxl_decoder_release+0x2a/0x60 [cxl_core]
device_release+0x5f/0x100
kobject_cleanup+0x80/0x1c0
The device core only guarantees parent lifetime until all children are
unregistered. If a child needs a parent to complete its ->release()
callback that child needs to hold a reference to extend the lifetime of
the parent.
Fixes: 40ba17afdfab ("cxl/acpi: Introduce cxl_decoder objects")
Reported-by: Ben Widawsky <ben.widawsky@intel.com>
Tested-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Ben Widawsky <ben.widawsky@intel.com>
Link: https://lore.kernel.org/r/164505751190.4175768.13324905271463416712.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/cxl')
| -rw-r--r-- | drivers/cxl/core/port.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c index 0fc1441be014..c1681248f322 100644 --- a/drivers/cxl/core/port.c +++ b/drivers/cxl/core/port.c @@ -251,6 +251,7 @@ static void cxl_decoder_release(struct device *dev) ida_free(&port->decoder_ida, cxld->id); kfree(cxld); + put_device(&port->dev); } static const struct device_type cxl_decoder_endpoint_type = { @@ -1202,7 +1203,10 @@ static struct cxl_decoder *cxl_decoder_alloc(struct cxl_port *port, if (rc < 0) goto err; + /* need parent to stick around to release the id */ + get_device(&port->dev); cxld->id = rc; + cxld->nr_targets = nr_targets; seqlock_init(&cxld->target_lock); dev = &cxld->dev; |