Sahitya Tummala cf535659b3 block: Fix use-after-free issue accessing struct io_cq ... [ Upstream commit 30a2da7b7e ] There is a potential race between ioc_release_fn() and ioc_clear_queue() as shown below, due to which below kernel crash is observed. It also can result into use-after-free issue. context#1: context#2: ioc_release_fn() __ioc_clear_queue() gets the same icq ->spin_lock(&ioc->lock); ->spin_lock(&ioc->lock); ->ioc_destroy_icq(icq); ->list_del_init(&icq->q_node); ->call_rcu(&icq->__rcu_head, icq_free_icq_rcu); ->spin_unlock(&ioc->lock); ->ioc_destroy_icq(icq); ->hlist_del_init(&icq->ioc_node); This results into below crash as this memory is now used by icq->__rcu_head in context#1. There is a chance that icq could be free'd as well. 22150.386550: <6> Unable to handle kernel write to read-only memory at virtual address ffffffaa8d31ca50 ... Call trace: 22150.607350: <2> ioc_destroy_icq+0x44/0x110 22150.611202: <2> ioc_clear_queue+0xac/0x148 22150.615056: <2> blk_cleanup_queue+0x11c/0x1a0 22150.619174: <2> __scsi_remove_device+0xdc/0x128 22150.623465: <2> scsi_forget_host+0x2c/0x78 22150.627315: <2> scsi_remove_host+0x7c/0x2a0 22150.631257: <2> usb_stor_disconnect+0x74/0xc8 22150.635371: <2> usb_unbind_interface+0xc8/0x278 22150.639665: <2> device_release_driver_internal+0x198/0x250 22150.644897: <2> device_release_driver+0x24/0x30 22150.649176: <2> bus_remove_device+0xec/0x140 22150.653204: <2> device_del+0x270/0x460 22150.656712: <2> usb_disable_device+0x120/0x390 22150.660918: <2> usb_disconnect+0xf4/0x2e0 22150.664684: <2> hub_event+0xd70/0x17e8 22150.668197: <2> process_one_work+0x210/0x480 22150.672222: <2> worker_thread+0x32c/0x4c8 Fix this by adding a new ICQ_DESTROYED flag in ioc_destroy_icq() to indicate this icq is once marked as destroyed. Also, ensure __ioc_clear_queue() is accessing icq within rcu_read_lock/unlock so that icq doesn't get free'd up while it is still using it. Signed-off-by: Sahitya Tummala <stummala@codeaurora.org> Co-developed-by: Pradeep P V K <ppvk@codeaurora.org> Signed-off-by: Pradeep P V K <ppvk@codeaurora.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>		2020-04-17 10:48:41 +02:00
..
acpi	ACPICA: Introduce ACPI_ACCESS_BYTE_WIDTH() macro	2020-03-05 16:42:17 +01:00
asm-generic	asm-generic: fix -Wtype-limits compiler warnings	2019-08-25 10:47:58 +02:00
clocksource
crypto	crypto: chacha20 - Fix chacha20_block() keystream alignment (again)	2019-11-20 18:47:11 +01:00
drm	drm/panel: make drm_panel.h self-contained	2020-01-27 14:51:01 +01:00
dt-bindings	dt-bindings: reset: meson8b: fix duplicate reset IDs	2020-01-23 08:21:26 +01:00
keys
kvm	KVM: arm/arm64: Sync ICH_VMCR_EL2 back when about to block	2019-08-25 10:47:59 +02:00
linux	block: Fix use-after-free issue accessing struct io_cq	2020-04-17 10:48:41 +02:00
math-emu	math-emu/soft-fp.h: (_FP_ROUND_ZERO) cast 0 to void to fix warning	2019-12-13 08:51:34 +01:00
media	media: v4l2-device.h: Explicitly compare grp{id,mask} to zero in v4l2_device macros	2020-02-24 08:34:41 +01:00
memory
misc
net	fib: add missing attribute validation for tun_id	2020-03-18 07:14:14 +01:00
pcmcia
ras
rdma	RDMA/uverbs: Verify MR access flags	2020-02-14 16:33:23 -05:00
scsi	scsi: Revert "target: iscsi: Wait for all commands to finish before freeing a session"	2020-02-28 16:38:58 +01:00
soc	soc/tegra: pmc: Fix pad voltage configuration for Tegra186	2019-11-20 18:45:24 +01:00
sound	ALSA: rawmidi: Avoid bit fields for state flags	2020-02-28 16:38:59 +01:00
target
trace	afs: Fix some tracing details	2020-04-02 15:28:19 +02:00
uapi	coresight: do not use the BIT() macro in the UAPI header	2020-04-13 10:45:03 +02:00
video
xen	xen/events: fix binding user event channels to cpus	2019-07-26 09:14:25 +02:00