Eric Dumazet e31e467255 dump_stack: avoid potential deadlocks ... commit d7ce36924344ace0dbdc855b1206cacc46b36d45 upstream. Some servers experienced fatal deadlocks because of a combination of bugs, leading to multiple cpus calling dump_stack(). The checksumming bug was fixed in commit 34ae6a1aa054 ("ipv6: update skb->csum when CE mark is propagated"). The second problem is a faulty locking in dump_stack() CPU1 runs in process context and calls dump_stack(), grabs dump_lock. CPU2 receives a TCP packet under softirq, grabs socket spinlock, and call dump_stack() from netdev_rx_csum_fault(). dump_stack() spins on atomic_cmpxchg(&dump_lock, -1, 2), since dump_lock is owned by CPU1 While dumping its stack, CPU1 is interrupted by a softirq, and happens to process a packet for the TCP socket locked by CPU2. CPU1 spins forever in spin_lock() : deadlock Stack trace on CPU1 looked like : NMI backtrace for cpu 1 RIP: _raw_spin_lock+0x25/0x30 ... Call Trace: <IRQ> tcp_v6_rcv+0x243/0x620 ip6_input_finish+0x11f/0x330 ip6_input+0x38/0x40 ip6_rcv_finish+0x3c/0x90 ipv6_rcv+0x2a9/0x500 process_backlog+0x461/0xaa0 net_rx_action+0x147/0x430 __do_softirq+0x167/0x2d0 call_softirq+0x1c/0x30 do_softirq+0x3f/0x80 irq_exit+0x6e/0xc0 smp_call_function_single_interrupt+0x35/0x40 call_function_single_interrupt+0x6a/0x70 <EOI> printk+0x4d/0x4f printk_address+0x31/0x33 print_trace_address+0x33/0x3c print_context_stack+0x7f/0x119 dump_trace+0x26b/0x28e show_trace_log_lvl+0x4f/0x5c show_stack_log_lvl+0x104/0x113 show_stack+0x42/0x44 dump_stack+0x46/0x58 netdev_rx_csum_fault+0x38/0x3c __skb_checksum_complete_head+0x6e/0x80 __skb_checksum_complete+0x11/0x20 tcp_rcv_established+0x2bd5/0x2fd0 tcp_v6_do_rcv+0x13c/0x620 sk_backlog_rcv+0x15/0x30 release_sock+0xd2/0x150 tcp_recvmsg+0x1c1/0xfc0 inet_recvmsg+0x7d/0x90 sock_recvmsg+0xaf/0xe0 ___sys_recvmsg+0x111/0x3b0 SyS_recvmsg+0x5c/0xb0 system_call_fastpath+0x16/0x1b Fixes: b58d977432 ("dump_stack: serialize the output from dump_stack()") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Alex Thorlton <athorlton@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2016-02-25 12:01:23 -08:00
..
842	crypto: 842 - Add CRC and validation support	2015-10-14 22:23:17 +08:00
fonts	fonts: Add 6x10 font	2014-10-09 11:35:48 +03:00
lz4	lz4: fix system halt at boot kernel on x86_64	2015-05-24 11:56:29 -07:00
lzo	lzo: check for length overrun in variable length encoding.	2014-09-28 11:08:01 +02:00
mpi	asm-generic cleanups	2015-11-06 14:22:15 -08:00
raid6	md/raid6: delta syndrome for ARM NEON	2015-08-31 19:29:05 +02:00
reed_solomon
xz	lib/xz: enable all filters by default in Kconfig	2014-06-04 16:54:18 -07:00
zlib_deflate	zlib_deflate/deftree: remove bi_reverse()	2015-09-10 13:29:01 -07:00
zlib_inflate	zlib: clean up some dead code	2014-08-06 18:01:24 -07:00
.gitignore
argv_split.c
asn1_decoder.c	ASN.1: Handle 'ANY OPTIONAL' in grammar	2015-08-05 13:38:07 +01:00
assoc_array.c	assoc_array: Include rcupdate.h for call_rcu() definition	2015-01-07 16:08:41 +00:00
atomic64.c	atomic: Provide atomic_{or,xor,and}	2015-07-27 14:06:24 +02:00
atomic64_test.c	atomic: Add simple atomic_t tests	2015-07-27 14:06:24 +02:00
audit.c	syscalls: implement execveat() system call	2014-12-13 12:42:51 -08:00
bcd.c
bch.c
bitmap.c	lib/bitmap.c: bitmap_parselist can accept string with whitespaces on head or tail	2015-09-10 13:29:01 -07:00
bitrev.c	ARM: 8187/1: add CONFIG_HAVE_ARCH_BITREVERSE to support rbit instruction	2014-12-22 16:43:06 +00:00
bsearch.c
btree.c	treewide: Remove old email address	2015-11-23 09:44:58 +01:00
bug.c	module: Sanitize RCU usage and locking	2015-05-28 11:31:52 +09:30
build_OID_registry
bust_spinlocks.c
check_signature.c
checksum.c	lib/checksum.c: fix build for generic csum_tcpudp_nofold	2015-01-29 11:57:38 -08:00
clz_ctz.c
clz_tab.c
cmdline.c	lib: Add a generic cmdline parse function parse_option_str	2014-10-03 18:40:58 +01:00
compat_audit.c
cordic.c
cpu-notifier-error-inject.c
cpu_rmap.c	sched/topology: Rename topology_thread_cpumask() to topology_sibling_cpumask()	2015-05-27 15:22:15 +02:00
cpumask.c	revert "cpumask: don't perform while loop in cpumask_next_and()"	2015-06-18 17:00:23 -10:00
crc-ccitt.c
crc-itu-t.c	lib: crc-itu-t.[ch] fix 0x0x prefix in integer constants	2015-05-26 15:26:43 +02:00
crc-t10dif.c	lib: introduce crc_t10dif_update()	2015-05-30 22:42:24 -07:00
crc7.c	lib/crc7: Shift crc7() output left 1 bit	2014-05-16 14:26:52 -04:00
crc8.c
crc16.c
crc32.c	lib: crc32: Add some additional __pure annotations	2014-06-25 16:04:00 -07:00
crc32defs.h
ctype.c
debug_info.c	kbuild: include core debug info when DEBUG_INFO_REDUCED	2015-06-11 15:08:32 +02:00
debug_locks.c
debugobjects.c	lib/debugobjects.c: convert printk(KERN_DEBUG to pr_debug	2014-06-04 16:53:53 -07:00
dec_and_lock.c
decompress.c	lib/decompress: set the compressor name to NULL on error	2015-07-17 16:39:54 -07:00
decompress_bunzip2.c	lib/decompressors: use real out buf size for gunzip with kernel	2015-09-10 13:29:01 -07:00
decompress_inflate.c	lib/decompressors: use real out buf size for gunzip with kernel	2015-09-10 13:29:01 -07:00
decompress_unlz4.c	lib/decompressors: use real out buf size for gunzip with kernel	2015-09-10 13:29:01 -07:00
decompress_unlzma.c	lib/decompress_unlzma: Do a NULL check for pointer	2015-09-10 13:29:01 -07:00
decompress_unlzo.c	lib/decompressors: use real out buf size for gunzip with kernel	2015-09-10 13:29:01 -07:00
decompress_unxz.c	lib/decompressors: use real out buf size for gunzip with kernel	2015-09-10 13:29:01 -07:00
devres.c	devres: fix a for loop bounds check	2015-10-05 04:49:54 +01:00
digsig.c	KEYS: Merge the type-specific data with the payload data	2015-10-21 15:18:36 +01:00
div64.c	remove abs64()	2015-11-09 15:11:24 -08:00
dma-debug.c	dma-debug: switch check from _text to _stext	2016-02-25 12:01:22 -08:00
dump_stack.c	dump_stack: avoid potential deadlocks	2016-02-25 12:01:23 -08:00
dynamic_debug.c	lib/dynamic_debug.c: use kstrdup_const	2015-11-06 17:50:42 -08:00
dynamic_queue_limits.c	lib/dynamic_queue_limits.c: simplify includes	2015-02-12 18:54:15 -08:00
earlycpio.c
extable.c
fault-inject.c	fault-inject: fix inverted interval/probability values in printk	2015-10-23 17:55:10 +09:00
fdt.c
fdt_empty_tree.c
fdt_ro.c
fdt_rw.c
fdt_strerror.c
fdt_sw.c
fdt_wip.c
find_bit.c	lib: rename lib/find_next_bit.c to lib/find_bit.c	2015-04-17 09:03:54 -04:00
flex_array.c
flex_proportions.c	proportions: add @gfp to init functions	2014-09-08 09:51:30 +09:00
gcd.c
gen_crc32table.c	lib: crc32: constify crc32 lookup table	2015-02-13 21:21:35 -08:00
genalloc.c	genalloc: add support of multiple gen_pools per device	2015-09-04 16:54:41 -07:00
glob.c	lib/glob.c: add CONFIG_GLOB_SELFTEST	2014-08-06 18:01:25 -07:00
halfmd4.c	lib/halfmd4.c: use rol32 inline function in the ROUND macro	2015-11-06 17:50:42 -08:00
hexdump.c	lib/hexdump.c: truncate output in case of overflow	2015-11-06 17:50:42 -08:00
hweight.c	Make ARCH_HAS_FAST_MULTIPLIER a real config variable	2014-09-13 11:14:53 -07:00
idr.c	mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd	2015-11-06 17:50:42 -08:00
inflate.c
int_sqrt.c
interval_tree.c	lib/interval_tree.c: simplify includes	2015-02-12 18:54:15 -08:00
interval_tree_test.c
iomap.c
iomap_copy.c
iommu-common.c	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc	2015-11-05 16:34:48 -08:00
iommu-helper.c
ioremap.c	x86, mm: support huge KVA mappings on x86	2015-04-14 16:49:04 -07:00
iov_iter.c	Merge branch 'iov_iter' into for-next	2015-04-11 22:26:51 -04:00
irq_regs.c
is_single_threaded.c	lib/is_single_threaded.c: change current_is_single_threaded() to use for_each_thread()	2015-11-06 17:50:42 -08:00
jedec_ddr_data.c
kasprintf.c	lib/kasprintf.c: introduce kvasprintf_const	2015-11-06 17:50:42 -08:00
Kconfig	lib/Kconfig: ZLIB_DEFLATE must select BITREVERSE	2015-10-16 11:42:28 -07:00
Kconfig.debug	Nothing exciting, minor tweaks and cleanups.	2015-11-09 15:53:39 -08:00
Kconfig.kasan	mm, slub, kasan: enable user tracking by default with KASAN=y	2015-11-05 19:34:48 -08:00
Kconfig.kgdb	kdb: Allow access to sensitive commands to be restricted by default	2014-11-11 09:31:52 -06:00
Kconfig.kmemcheck
kfifo.c	kfifo: use BUG_ON	2014-08-08 15:57:25 -07:00
klist.c	klist: fix starting point removed bug in klist iterators	2016-02-25 12:01:16 -08:00
kobject.c	lib/kobject.c: use kvasprintf_const for formatting ->name	2015-11-06 17:50:42 -08:00
kobject_uevent.c	lib/kobject_uevent.c: remove redundant include	2015-02-12 18:54:15 -08:00
kstrtox.c	kstrto*: accept "-0" for signed conversion	2015-09-10 13:29:01 -07:00
kstrtox.h
lcm.c	block: fix blk_stack_limits() regression due to lcm() change	2015-03-31 09:45:50 -06:00
libcrc32c.c	crypto: crc32c - Fix crc32c soft dependency	2016-02-17 12:31:04 -08:00
list_debug.c
list_sort.c	lib/list_sort: use late_initcall to hook in self tests	2015-06-16 14:12:35 -04:00
llist.c	lib/llist.c: fix data race in llist_del_first	2015-11-06 17:50:42 -08:00
locking-selftest-hardirq.h
locking-selftest-mutex.h
locking-selftest-rlock-hardirq.h
locking-selftest-rlock-softirq.h
locking-selftest-rlock.h
locking-selftest-rsem.h
locking-selftest-softirq.h
locking-selftest-spin-hardirq.h
locking-selftest-spin-softirq.h
locking-selftest-spin.h
locking-selftest-wlock-hardirq.h
locking-selftest-wlock-softirq.h
locking-selftest-wlock.h
locking-selftest-wsem.h
locking-selftest.c	locking/lockdep: Revert qrwlock recusive stuff	2014-10-03 06:09:30 +02:00
lockref.c	locking/lockref: Remove homebrew cmpxchg64_relaxed() macro definition	2015-08-12 11:59:04 +02:00
lru_cache.c	lru_cache: remove use of seq_printf return value	2015-04-15 16:35:25 -07:00
Makefile	test_printf: test printf family at runtime	2015-11-06 17:50:42 -08:00
md5.c	lib/md5.c: simplify include	2015-02-12 18:54:15 -08:00
memory-notifier-error-inject.c
memweight.c
net_utils.c	mac_pton: Use bool not int return	2014-06-25 17:45:43 -07:00
nlattr.c	netlink: pad nla_memcpy dest buffer with zeroes	2015-03-31 14:07:24 -04:00
nmi_backtrace.c	ARM: 8439/1: Fix backtrace generation when IPI is masked	2015-10-03 16:40:51 +01:00
notifier-error-inject.c
notifier-error-inject.h
of-reconfig-notifier-error-inject.c
oid_registry.c
once.c	once: make helper generic for calling functions once	2015-10-08 05:26:36 -07:00
parser.c
pci_iomap.c	libnvdimm for 4.3:	2015-09-08 14:35:59 -07:00
percpu-refcount.c	percpu_ref: make INIT_ATOMIC and switch_to_atomic() sticky	2014-09-24 13:31:50 -04:00
percpu_counter.c	percpu_counter: batch size aware __percpu_counter_compare()	2015-05-29 07:39:34 +10:00
percpu_ida.c	mm, page_alloc: rename __GFP_WAIT to __GFP_RECLAIM	2015-11-06 17:50:42 -08:00
percpu_test.c
plist.c	lib/plist.c: remove redundant include	2015-02-12 18:54:16 -08:00
pm-notifier-error-inject.c
proportions.c	treewide: Remove old email address	2015-11-23 09:44:58 +01:00
radix-tree.c	radix-tree: fix race in gang lookup	2016-02-25 12:01:23 -08:00
random32.c	random32: add prandom_init_once helper for own rngs	2015-10-08 05:26:38 -07:00
ratelimit.c
rational.c
rbtree.c	rbtree: Make lockless searches non-fatal	2015-05-28 11:32:04 +09:30
rbtree_test.c
reciprocal_div.c
rhashtable.c	rhashtable: Kill harmless RCU warning in rhashtable_walk_init	2015-12-18 23:44:18 -05:00
scatterlist.c	scatterlist: allow limited chaining without ARCH_HAS_SG_CHAIN	2015-08-17 08:12:51 -06:00
seq_buf.c	seq_buf: Fix seq_buf_bprintf() truncation	2015-03-04 23:40:19 -05:00
sg_split.c	lib: scatterlist: add sg splitting function	2015-08-24 14:28:01 -06:00
sha1.c	lib: EXPORT_SYMBOL sha_init	2015-03-23 22:12:08 -04:00
show_mem.c	lib/show_mem.c: correct reserved memory calculation	2015-09-08 15:35:28 -07:00
smp_processor_id.c
sort.c	lib/sort: Add 64 bit swap function	2015-06-25 17:00:40 -07:00
stmp_device.c	lib/stmp_device.c: replace module.h include	2015-02-12 18:54:16 -08:00
string.c	lib/string.c: add ULL suffix to the constant definition	2015-11-10 16:32:11 -08:00
string_helpers.c	string_helpers: fix precision loss for some inputs	2016-02-25 12:01:21 -08:00
strncpy_from_user.c	lib: move strncpy_from_unsafe() into mm/maccess.c	2015-08-31 12:36:10 -07:00
strnlen_user.c	Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-06-22 15:52:04 -07:00
swiotlb.c	Merge branch 'for-4.2/sg' of git://git.kernel.dk/linux-block	2015-06-25 15:22:36 -07:00
syscall.c
test-hexdump.c	hexdump: Make test data really const	2015-06-25 17:00:40 -07:00
test-kstrtox.c	kstrto*: accept "-0" for signed conversion	2015-09-10 13:29:01 -07:00
test-string_helpers.c	lib/test-string_helpers.c: add string_get_size() tests	2015-11-06 17:50:42 -08:00
test_bpf.c	bpf: add mod default A and X test cases	2015-11-05 00:05:50 -05:00
test_firmware.c	test: add firmware_class loader test	2014-07-17 18:44:19 -07:00
test_kasan.c	lib: test_kasan: add some testcases	2015-11-05 19:34:48 -08:00
test_module.c
test_printf.c	test_printf: test printf family at runtime	2015-11-06 17:50:42 -08:00
test_rhashtable.c	rhashtable-test: extend to test concurrency	2015-08-17 14:33:47 -07:00
test_static_key_base.c	locking/static_keys: Provide a selftest	2015-08-03 11:51:12 +02:00
test_static_keys.c	locking/static_keys: Make verify_keys() static	2015-08-05 09:53:40 +02:00
test_user_copy.c
textsearch.c	lib/textsearch.c: remove textsearch_put reference from comments	2014-10-14 02:18:14 +02:00
timerqueue.c	timerqueue: Let timerqueue_add/del return information	2015-04-22 17:06:49 +02:00
ts_bm.c
ts_fsm.c
ts_kmp.c
ucs2_string.c
usercopy.c
uuid.c
vsprintf.c	lib/vsprintf.c: update documentation	2015-11-06 17:50:42 -08:00