Sun Ke cde4b55cfb nbd: Fix NULL pointer in flush_workqueue ... [ Upstream commit 79ebe9110fa458d58f1fceb078e2068d7ad37390 ] Open /dev/nbdX first, the config_refs will be 1 and the pointers in nbd_device are still null. Disconnect /dev/nbdX, then reference a null recv_workq. The protection by config_refs in nbd_genl_disconnect is useless. [ 656.366194] BUG: kernel NULL pointer dereference, address: 0000000000000020 [ 656.368943] #PF: supervisor write access in kernel mode [ 656.369844] #PF: error_code(0x0002) - not-present page [ 656.370717] PGD 10cc87067 P4D 10cc87067 PUD 1074b4067 PMD 0 [ 656.371693] Oops: 0002 [#1] SMP [ 656.372242] CPU: 5 PID: 7977 Comm: nbd-client Not tainted 5.11.0-rc5-00040-g76c057c84d28 #1 [ 656.373661] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014 [ 656.375904] RIP: 0010:mutex_lock+0x29/0x60 [ 656.376627] Code: 00 0f 1f 44 00 00 55 48 89 fd 48 83 05 6f d7 fe 08 01 e8 7a c3 ff ff 48 83 05 6a d7 fe 08 01 31 c0 65 48 8b 14 25 00 6d 01 00 <f0> 48 0f b1 55 d [ 656.378934] RSP: 0018:ffffc900005eb9b0 EFLAGS: 00010246 [ 656.379350] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 656.379915] RDX: ffff888104cf2600 RSI: ffffffffaae8f452 RDI: 0000000000000020 [ 656.380473] RBP: 0000000000000020 R08: 0000000000000000 R09: ffff88813bd6b318 [ 656.381039] R10: 00000000000000c7 R11: fefefefefefefeff R12: ffff888102710b40 [ 656.381599] R13: ffffc900005eb9e0 R14: ffffffffb2930680 R15: ffff88810770ef00 [ 656.382166] FS: 00007fdf117ebb40(0000) GS:ffff88813bd40000(0000) knlGS:0000000000000000 [ 656.382806] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 656.383261] CR2: 0000000000000020 CR3: 0000000100c84000 CR4: 00000000000006e0 [ 656.383819] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 656.384370] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 656.384927] Call Trace: [ 656.385111] flush_workqueue+0x92/0x6c0 [ 656.385395] nbd_disconnect_and_put+0x81/0xd0 [ 656.385716] nbd_genl_disconnect+0x125/0x2a0 [ 656.386034] genl_family_rcv_msg_doit.isra.0+0x102/0x1b0 [ 656.386422] genl_rcv_msg+0xfc/0x2b0 [ 656.386685] ? nbd_ioctl+0x490/0x490 [ 656.386954] ? genl_family_rcv_msg_doit.isra.0+0x1b0/0x1b0 [ 656.387354] netlink_rcv_skb+0x62/0x180 [ 656.387638] genl_rcv+0x34/0x60 [ 656.387874] netlink_unicast+0x26d/0x590 [ 656.388162] netlink_sendmsg+0x398/0x6c0 [ 656.388451] ? netlink_rcv_skb+0x180/0x180 [ 656.388750] ____sys_sendmsg+0x1da/0x320 [ 656.389038] ? ____sys_recvmsg+0x130/0x220 [ 656.389334] ___sys_sendmsg+0x8e/0xf0 [ 656.389605] ? ___sys_recvmsg+0xa2/0xf0 [ 656.389889] ? handle_mm_fault+0x1671/0x21d0 [ 656.390201] __sys_sendmsg+0x6d/0xe0 [ 656.390464] __x64_sys_sendmsg+0x23/0x30 [ 656.390751] do_syscall_64+0x45/0x70 [ 656.391017] entry_SYSCALL_64_after_hwframe+0x44/0xa9 To fix it, just add if (nbd->recv_workq) to nbd_disconnect_and_put(). Fixes: e9e006f5fc ("nbd: fix max number of supported devs") Signed-off-by: Sun Ke <sunke32@huawei.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Link: https://lore.kernel.org/r/20210512114331.1233964-2-sunke32@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>		2021-05-19 10:13:14 +02:00
..
aoe	block: lift setting the readahead size into the block layer	2020-09-24 13:43:39 -06:00
drbd	block-5.10-2020-10-12	2020-10-13 12:12:44 -07:00
mtip32xx
paride	paride/pcd: use bdev_check_media_change	2020-09-10 09:32:31 -06:00
rnbd	block/rnbd-clt: Check the return value of the function rtrs_clt_query	2021-05-19 10:13:06 +02:00
rsxx	block: rsxx: fix error return code of rsxx_pci_probe()	2021-03-17 17:06:33 +01:00
xen-blkback	xen-blkback: fix compatibility bug with single page rings	2021-05-14 09:50:21 +02:00
zram	zram: fix return value on writeback_store	2021-03-17 17:06:34 +01:00
amiflop.c	amiflop: use bdev_check_media_change	2020-09-10 09:32:30 -06:00
ataflop.c	ataflop: use bdev_check_media_change	2020-09-10 09:32:30 -06:00
brd.c	bdi: remove BDI_CAP_SYNCHRONOUS_IO	2020-09-24 13:43:39 -06:00
cryptoloop.c
floppy.c	floppy: reintroduce O_NDELAY fix	2021-03-04 11:38:33 +01:00
Kconfig	block: rsxx: select CONFIG_CRC32	2021-01-17 14:17:03 +01:00
loop.c	loop: Fix occasional uevent drop	2020-11-12 13:59:04 -07:00
loop.h
Makefile
nbd.c	nbd: Fix NULL pointer in flush_workqueue	2021-05-19 10:13:14 +02:00
null_blk_main.c	null_blk: fix command timeout completion handling	2021-04-16 11:43:21 +02:00
null_blk_trace.c
null_blk_trace.h
null_blk_zoned.c	drivers/block/null_blk/main: Fix a double free in null_init.	2021-05-14 09:50:28 +02:00
null_blk.h	null_blk: fix command timeout completion handling	2021-04-16 11:43:21 +02:00
pktcdvd.c	pktcdvd: use blkdev_get_by_dev instead of open coding it	2020-09-23 10:43:19 -06:00
ps3disk.c
ps3vram.c
rbd_types.h
rbd.c	We have:	2020-10-21 10:34:10 -07:00
skd_main.c	skd_main: remove unused including <linux/version.h>	2020-10-17 08:11:14 -06:00
skd_s1120.h
sunvdc.c
swim_asm.S
swim.c	swim: simplify media change handling	2020-09-10 09:32:30 -06:00
swim3.c	swim3: use bdev_check_media_changed	2020-09-10 09:32:31 -06:00
sx8.c
umem.c	umem: fix error return code in mm_pci_probe()	2021-03-30 14:31:50 +02:00
umem.h
virtio_blk.c	block: add a new revalidate_disk_size helper	2020-09-02 08:00:07 -06:00
xen-blkfront.c	xen-blkfront: allow discard-* nodes to be optional	2021-02-03 23:28:44 +01:00
xsysace.c	xsysace: use platform_get_resource() and platform_get_irq_optional()	2020-10-29 08:22:33 -06:00
z2ram.c