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Eric Dumazet 0355d6c1d5 kcm: disable preemption in kcm_parse_func_strparser()
After commit a2c11b0341 ("kcm: use BPF_PROG_RUN")
syzbot easily triggers the warning in cant_sleep().

As explained in commit 6cab5e90ab ("bpf: run bpf programs
with preemption disabled") we need to disable preemption before
running bpf programs.

BUG: assuming atomic context at net/kcm/kcmsock.c:382
in_atomic(): 0, irqs_disabled(): 0, pid: 7, name: kworker/u4:0
3 locks held by kworker/u4:0/7:
 #0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline]
 #0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline]
 #0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline]
 #0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: set_work_data kernel/workqueue.c:620 [inline]
 #0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:647 [inline]
 #0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2240
 #1: ffff8880a989fdc0 ((work_completion)(&strp->work)){+.+.}, at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2244
 #2: ffff888098998d10 (sk_lock-AF_INET){+.+.}, at: lock_sock include/net/sock.h:1522 [inline]
 #2: ffff888098998d10 (sk_lock-AF_INET){+.+.}, at: strp_sock_lock+0x2e/0x40 net/strparser/strparser.c:440
CPU: 0 PID: 7 Comm: kworker/u4:0 Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: kstrp strp_work
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 __cant_sleep kernel/sched/core.c:6826 [inline]
 __cant_sleep.cold+0xa4/0xbc kernel/sched/core.c:6803
 kcm_parse_func_strparser+0x54/0x200 net/kcm/kcmsock.c:382
 __strp_recv+0x5dc/0x1b20 net/strparser/strparser.c:221
 strp_recv+0xcf/0x10b net/strparser/strparser.c:343
 tcp_read_sock+0x285/0xa00 net/ipv4/tcp.c:1639
 strp_read_sock+0x14d/0x200 net/strparser/strparser.c:366
 do_strp_work net/strparser/strparser.c:414 [inline]
 strp_work+0xe3/0x130 net/strparser/strparser.c:423
 process_one_work+0x9af/0x1740 kernel/workqueue.c:2269

Fixes: a2c11b0341 ("kcm: use BPF_PROG_RUN")
Fixes: 6cab5e90ab ("bpf: run bpf programs with preemption disabled")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-09-27 10:27:14 +02:00
Documentation dt-bindings: net: ravb: Add support for r8a774b1 SoC 2019-09-26 09:30:13 +02:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch Merge branch 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-09-18 13:03:01 -07:00
block for-5.4/block-2019-09-16 2019-09-17 16:57:47 -07:00
certs Revert "Merge tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs" 2019-07-10 18:43:43 -07:00
crypto padata, pcrypt: take CPU hotplug lock internally in padata_alloc_possible 2019-09-13 21:15:40 +10:00
drivers net: ethernet: stmmac: Fix signedness bug in ipq806x_gmac_of_parse() 2019-09-27 10:21:44 +02:00
fs New code for 5.4: 2019-09-18 18:32:43 -07:00
include net/mlx5: DR, Fix SW steering HW bits and definitions 2019-09-24 12:38:06 +03:00
init Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-09-17 12:35:15 -07:00
ipc Merge branch 'work.mount-base' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-09-18 13:15:58 -07:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2019-09-18 12:34:53 -07:00
lib dimlib: make DIMLIB a hidden symbol 2019-09-27 09:47:54 +02:00
mm New code for 5.4: 2019-09-18 18:32:43 -07:00
net kcm: disable preemption in kcm_parse_func_strparser() 2019-09-27 10:27:14 +02:00
samples samples/bpf: fix xdpsock l2fwd tx for unaligned mode 2019-09-16 09:35:10 +02:00
scripts Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2019-09-18 12:34:53 -07:00
security keys: Fix missing null pointer check in request_key_auth_describe() 2019-09-05 14:19:25 -07:00
sound LED updates for 5.4-rc1 2019-09-17 18:40:42 -07:00
tools ipv6: do not free rt if FIB_LOOKUP_NOREF is set on suppress rule 2019-09-26 09:34:25 +02:00
usr kbuild: enable arch/s390/include/uapi/asm/zcrypt.h for uapi header test 2019-07-23 10:45:46 +02:00
virt * s390: ioctl hardening, selftests 2019-09-18 09:49:13 -07:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
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.gitignore .gitignore: Add compilation database file 2019-07-27 12:18:19 +09:00
.mailmap Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2019-09-18 12:34:53 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS CREDITS: Update email address 2019-09-13 17:21:38 +03:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS MAINTAINERS: add Yanjun to FORCEDETH maintainers list 2019-09-26 08:51:21 +02:00
Makefile arm64 updates for 5.4: 2019-09-16 14:31:40 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.