Dan Williams 49f2dab77a cxl/port: Hold port reference until decoder release ... [ Upstream commit 74be98774d ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org>		2022-04-08 13:58:07 +02:00
..
core.h
Makefile	cxl/core/port: Rename bus.c to port.c	2022-04-08 13:58:07 +02:00
mbox.c	cxl/core: Convert to EXPORT_SYMBOL_NS_GPL	2021-11-15 11:02:59 -08:00
memdev.c	cxl/core: Convert to EXPORT_SYMBOL_NS_GPL	2021-11-15 11:02:59 -08:00
pmem.c	cxl/pmem: Fix module reload vs workqueue state	2021-11-15 11:03:00 -08:00
port.c	cxl/port: Hold port reference until decoder release	2022-04-08 13:58:07 +02:00
regs.c	cxl/regs: Fix size of CXL Capability Header Register	2022-04-08 13:58:05 +02:00