Omar Sandoval 0b6b4b90b7 kyber: fix out of bounds access when preempted ... [ Upstream commit efed9a3337e341bd0989161b97453b52567bc59d ] __blk_mq_sched_bio_merge() gets the ctx and hctx for the current CPU and passes the hctx to ->bio_merge(). kyber_bio_merge() then gets the ctx for the current CPU again and uses that to get the corresponding Kyber context in the passed hctx. However, the thread may be preempted between the two calls to blk_mq_get_ctx(), and the ctx returned the second time may no longer correspond to the passed hctx. This "works" accidentally most of the time, but it can cause us to read garbage if the second ctx came from an hctx with more ctx's than the first one (i.e., if ctx->index_hw[hctx->type] > hctx->nr_ctx). This manifested as this UBSAN array index out of bounds error reported by Jakub: UBSAN: array-index-out-of-bounds in ../kernel/locking/qspinlock.c:130:9 index 13106 is out of range for type 'long unsigned int [128]' Call Trace: dump_stack+0xa4/0xe5 ubsan_epilogue+0x5/0x40 __ubsan_handle_out_of_bounds.cold.13+0x2a/0x34 queued_spin_lock_slowpath+0x476/0x480 do_raw_spin_lock+0x1c2/0x1d0 kyber_bio_merge+0x112/0x180 blk_mq_submit_bio+0x1f5/0x1100 submit_bio_noacct+0x7b0/0x870 submit_bio+0xc2/0x3a0 btrfs_map_bio+0x4f0/0x9d0 btrfs_submit_data_bio+0x24e/0x310 submit_one_bio+0x7f/0xb0 submit_extent_page+0xc4/0x440 __extent_writepage_io+0x2b8/0x5e0 __extent_writepage+0x28d/0x6e0 extent_write_cache_pages+0x4d7/0x7a0 extent_writepages+0xa2/0x110 do_writepages+0x8f/0x180 __writeback_single_inode+0x99/0x7f0 writeback_sb_inodes+0x34e/0x790 __writeback_inodes_wb+0x9e/0x120 wb_writeback+0x4d2/0x660 wb_workfn+0x64d/0xa10 process_one_work+0x53a/0xa80 worker_thread+0x69/0x5b0 kthread+0x20b/0x240 ret_from_fork+0x1f/0x30 Only Kyber uses the hctx, so fix it by passing the request_queue to ->bio_merge() instead. BFQ and mq-deadline just use that, and Kyber can map the queues itself to avoid the mismatch. Fixes: a6088845c2 ("block: kyber: make kyber more friendly with merging") Reported-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Omar Sandoval <osandov@fb.com> Link: https://lore.kernel.org/r/c7598605401a48d5cfeadebb678abd10af22b83f.1620691329.git.osandov@fb.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>		2021-05-19 10:08:30 +02:00
..
acpi	ACPI: scan: Use unique number for instance_no	2021-03-30 14:35:28 +02:00
asm-generic	vmlinux.lds.h: add DWARF v5 sections	2021-03-04 10:26:09 +01:00
clocksource
crypto	crypto: api - check for ERR pointers in crypto_destroy_tfm()	2021-05-11 14:04:05 +02:00
drm	iommu/vt-d: Move intel_iommu_gfx_mapped to Intel IOMMU header	2020-11-24 13:29:17 +01:00
dt-bindings	clk: imx8mn: Fix incorrect clock defines	2020-03-18 07:17:55 +01:00
keys	KEYS: Don't write out to userspace while holding key semaphore	2020-04-23 10:36:45 +02:00
kvm
linux	kyber: fix out of bounds access when preempted	2021-05-19 10:08:30 +02:00
math-emu
media	media: rc: compile rc-cec.c into rc-core	2021-03-17 17:03:40 +01:00
misc
net	net: bridge: mcast: fix broken length + header check for MRDv6 Adv.	2021-05-14 09:44:32 +02:00
pcmcia
ras
rdma	RDMA/umem: Fix signature of stub ib_umem_find_best_pgsz()	2020-10-29 09:57:47 +01:00
scsi	Fix misc new gcc warnings	2021-05-11 14:04:16 +02:00
soc	irqchip/eznps: Fix build error for !ARC700 builds	2020-09-17 13:47:47 +02:00
sound	ALSA: hda: intel-nhlt: verify config type	2021-03-09 11:09:39 +01:00
target	scsi: target: core: Add cmd length set before cmd complete	2021-03-17 17:03:45 +01:00
trace	writeback: Drop I_DIRTY_TIME_EXPIRE	2021-01-30 13:54:11 +01:00
uapi	netfilter: xt_SECMARK: add new revision to fix structure layout	2021-05-19 10:08:27 +02:00
vdso
video
xen	Xen/gntdev: correct error checking in gntdev_map_grant_pages()	2021-02-23 15:02:26 +01:00