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OpenCloudOS-Kernel/drivers/cxl/core
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Dan Williams 74be98774d 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: 40ba17afdf ("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>
 		2022-02-17 16:51:13 -08:00
..
Makefile cxl/core/hdm: Add CXL standard decoder enumeration to the core 2022-02-08 22:57:30 -08:00
core.h cxl/core/hdm: Add CXL standard decoder enumeration to the core 2022-02-08 22:57:30 -08:00
hdm.c cxl/core/port: Handle invalid decoders 2022-02-08 23:15:10 -08:00
mbox.c cxl/core: Convert to EXPORT_SYMBOL_NS_GPL 2021-11-15 11:02:59 -08:00
memdev.c cxl/mem: Add the cxl_mem driver 2022-02-08 22:57:32 -08:00
pci.c cxl/core/port: Remove @host argument for dport + decoder enumeration 2022-02-08 22:57:30 -08:00
pmem.c cxl/pmem: Introduce a find_cxl_root() helper 2022-02-08 22:57:29 -08:00
port.c cxl/port: Hold port reference until decoder release 2022-02-17 16:51:13 -08:00
regs.c cxl/regs: Fix size of CXL Capability Header Register 2022-02-08 23:15:33 -08:00