Dan Williams 518bb96367 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>		2022-07-12 16:34:58 +02:00
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core	cxl/port: Hold port reference until decoder release	2022-07-12 16:34:58 +02:00
acpi.c	cxl/acpi: Do not add DSDT disabled ACPI0016 host bridge ports	2021-09-07 11:39:01 -07:00
cxl.h	cxl/pci: Simplify register setup	2021-08-06 08:27:02 -07:00
cxlmem.h	cxl/mem: Account for partitionable space in ram/pmem ranges	2021-08-10 11:57:59 -07:00
Kconfig	cxl/pmem: Add initial infrastructure for pmem support	2021-06-15 16:47:14 -07:00
Makefile	cxl: Move cxl_core to new directory	2021-08-06 08:22:53 -07:00
pci.c	cxl/pci: Fix NULL vs ERR_PTR confusion	2021-11-18 19:16:04 +01:00
pci.h	cxl/pci: Simplify register setup	2021-08-06 08:27:02 -07:00
pmem.c	cxl/pmem: Fix reference counting for delayed work	2022-01-27 11:02:58 +01:00