Sergey Senozhatsky 656d61ce96 lib/ratelimit.c: use deferred printk() version ... printk_ratelimit() invokes ___ratelimit() which may invoke a normal printk() (pr_warn() in this particular case) to warn about suppressed output. Given that printk_ratelimit() may be called from anywhere, that pr_warn() is dangerous - it may end up deadlocking the system. Fix ___ratelimit() by using deferred printk(). Sasha reported the following lockdep error: : Unregister pv shared memory for cpu 8 : select_fallback_rq: 3 callbacks suppressed : process 8583 (trinity-c78) no longer affine to cpu8 : : ====================================================== : WARNING: possible circular locking dependency detected : 4.14.0-rc2-next-20170927+ #252 Not tainted : ------------------------------------------------------ : migration/8/62 is trying to acquire lock: : (&port_lock_key){-.-.}, at: serial8250_console_write() : : but task is already holding lock: : (&rq->lock){-.-.}, at: sched_cpu_dying() : : which lock already depends on the new lock. : : : the existing dependency chain (in reverse order) is: : : -> #3 (&rq->lock){-.-.}: : __lock_acquire() : lock_acquire() : _raw_spin_lock() : task_fork_fair() : sched_fork() : copy_process.part.31() : _do_fork() : kernel_thread() : rest_init() : start_kernel() : x86_64_start_reservations() : x86_64_start_kernel() : verify_cpu() : : -> #2 (&p->pi_lock){-.-.}: : __lock_acquire() : lock_acquire() : _raw_spin_lock_irqsave() : try_to_wake_up() : default_wake_function() : woken_wake_function() : __wake_up_common() : __wake_up_common_lock() : __wake_up() : tty_wakeup() : tty_port_default_wakeup() : tty_port_tty_wakeup() : uart_write_wakeup() : serial8250_tx_chars() : serial8250_handle_irq.part.25() : serial8250_default_handle_irq() : serial8250_interrupt() : __handle_irq_event_percpu() : handle_irq_event_percpu() : handle_irq_event() : handle_level_irq() : handle_irq() : do_IRQ() : ret_from_intr() : native_safe_halt() : default_idle() : arch_cpu_idle() : default_idle_call() : do_idle() : cpu_startup_entry() : rest_init() : start_kernel() : x86_64_start_reservations() : x86_64_start_kernel() : verify_cpu() : : -> #1 (&tty->write_wait){-.-.}: : __lock_acquire() : lock_acquire() : _raw_spin_lock_irqsave() : __wake_up_common_lock() : __wake_up() : tty_wakeup() : tty_port_default_wakeup() : tty_port_tty_wakeup() : uart_write_wakeup() : serial8250_tx_chars() : serial8250_handle_irq.part.25() : serial8250_default_handle_irq() : serial8250_interrupt() : __handle_irq_event_percpu() : handle_irq_event_percpu() : handle_irq_event() : handle_level_irq() : handle_irq() : do_IRQ() : ret_from_intr() : native_safe_halt() : default_idle() : arch_cpu_idle() : default_idle_call() : do_idle() : cpu_startup_entry() : rest_init() : start_kernel() : x86_64_start_reservations() : x86_64_start_kernel() : verify_cpu() : : -> #0 (&port_lock_key){-.-.}: : check_prev_add() : __lock_acquire() : lock_acquire() : _raw_spin_lock_irqsave() : serial8250_console_write() : univ8250_console_write() : console_unlock() : vprintk_emit() : vprintk_default() : vprintk_func() : printk() : ___ratelimit() : __printk_ratelimit() : select_fallback_rq() : sched_cpu_dying() : cpuhp_invoke_callback() : take_cpu_down() : multi_cpu_stop() : cpu_stopper_thread() : smpboot_thread_fn() : kthread() : ret_from_fork() : : other info that might help us debug this: : : Chain exists of: : &port_lock_key --> &p->pi_lock --> &rq->lock : : Possible unsafe locking scenario: : : CPU0 CPU1 : ---- ---- : lock(&rq->lock); : lock(&p->pi_lock); : lock(&rq->lock); : lock(&port_lock_key); : : *** DEADLOCK *** : : 4 locks held by migration/8/62: : #0: (&p->pi_lock){-.-.}, at: sched_cpu_dying() : #1: (&rq->lock){-.-.}, at: sched_cpu_dying() : #2: (printk_ratelimit_state.lock){....}, at: ___ratelimit() : #3: (console_lock){+.+.}, at: vprintk_emit() : : stack backtrace: : CPU: 8 PID: 62 Comm: migration/8 Not tainted 4.14.0-rc2-next-20170927+ #252 : Call Trace: : dump_stack() : print_circular_bug() : check_prev_add() : ? add_lock_to_list.isra.26() : ? check_usage() : ? kvm_clock_read() : ? kvm_sched_clock_read() : ? sched_clock() : ? check_preemption_disabled() : __lock_acquire() : ? __lock_acquire() : ? add_lock_to_list.isra.26() : ? debug_check_no_locks_freed() : ? memcpy() : lock_acquire() : ? serial8250_console_write() : _raw_spin_lock_irqsave() : ? serial8250_console_write() : serial8250_console_write() : ? serial8250_start_tx() : ? lock_acquire() : ? memcpy() : univ8250_console_write() : console_unlock() : ? __down_trylock_console_sem() : vprintk_emit() : vprintk_default() : vprintk_func() : printk() : ? show_regs_print_info() : ? lock_acquire() : ___ratelimit() : __printk_ratelimit() : select_fallback_rq() : sched_cpu_dying() : ? sched_cpu_starting() : ? rcutree_dying_cpu() : ? sched_cpu_starting() : cpuhp_invoke_callback() : ? cpu_disable_common() : take_cpu_down() : ? trace_hardirqs_off_caller() : ? cpuhp_invoke_callback() : multi_cpu_stop() : ? __this_cpu_preempt_check() : ? cpu_stop_queue_work() : cpu_stopper_thread() : ? cpu_stop_create() : smpboot_thread_fn() : ? sort_range() : ? schedule() : ? __kthread_parkme() : kthread() : ? sort_range() : ? kthread_create_on_node() : ret_from_fork() : process 9121 (trinity-c78) no longer affine to cpu8 : smpboot: CPU 8 is now offline Link: http://lkml.kernel.org/r/20170928120405.18273-1-sergey.senozhatsky@gmail.com Fixes: 6b1d174b0c ("ratelimit: extend to print suppressed messages on release") Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reported-by: Sasha Levin <levinsasha928@gmail.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Borislav Petkov <bp@suse.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2017-10-03 17:54:26 -07:00
..
842
fonts
lz4	lib/lz4: make arrays static const, reduces object code size	2017-10-03 17:54:25 -07:00
lzo
mpi
raid6	Merge tag 'md/4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md	2017-09-07 12:41:48 -07:00
reed_solomon
xz
zlib_deflate
zlib_inflate
zstd
.gitignore
argv_split.c
asn1_decoder.c
assoc_array.c
atomic64.c
atomic64_test.c
audit.c
bcd.c
bch.c
bitmap.c	lib/bitmap.c: make bitmap_parselist() thread-safe and much faster	2017-09-08 18:26:49 -07:00
bitrev.c
bsearch.c
btree.c
bug.c
build_OID_registry
bust_spinlocks.c
chacha20.c
check_signature.c
checksum.c
clz_ctz.c
clz_tab.c
cmdline.c	lib/cmdline.c: remove meaningless comment	2017-09-08 18:26:49 -07:00
compat_audit.c
cordic.c
cpu_rmap.c
cpumask.c	cpumask: make cpumask_next() out-of-line	2017-09-08 18:26:51 -07:00
crc-ccitt.c
crc-itu-t.c
crc-t10dif.c
crc4.c
crc7.c
crc8.c
crc16.c
crc32.c
crc32defs.h
crc32test.c
ctype.c
debug_info.c
debug_locks.c
debugobjects.c
dec_and_lock.c
decompress.c
decompress_bunzip2.c
decompress_inflate.c
decompress_unlz4.c
decompress_unlzma.c
decompress_unlzo.c
decompress_unxz.c
devres.c
digsig.c
div64.c
dma-debug.c
dma-noop.c
dma-virt.c
dump_stack.c
dynamic_debug.c
dynamic_queue_limits.c
earlycpio.c
errseq.c
extable.c
fault-inject.c
fdt.c
fdt_empty_tree.c
fdt_ro.c
fdt_rw.c
fdt_strerror.c
fdt_sw.c
fdt_wip.c
find_bit.c
flex_array.c
flex_proportions.c
gcd.c
gen_crc32table.c
genalloc.c
glob.c
globtest.c
hexdump.c	lib/hexdump.c: return -EINVAL in case of error in hex2bin()	2017-09-08 18:26:49 -07:00
hweight.c
idr.c	lib/idr.c: fix comment for idr_replace()	2017-10-03 17:54:25 -07:00
inflate.c
int_sqrt.c
interval_tree.c
interval_tree_test.c	lib/interval_tree: fast overlap detection	2017-09-08 18:26:49 -07:00
iomap.c
iomap_copy.c
iommu-common.c
iommu-helper.c
ioremap.c
iov_iter.c	iov_iter: fix page_copy_sane for compound pages	2017-09-20 23:27:48 -04:00
irq_poll.c
irq_regs.c
is_single_threaded.c
jedec_ddr_data.c
kasprintf.c
Kconfig	Merge branch 'zstd-minimal' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs	2017-09-14 17:30:49 -07:00
Kconfig.debug	parisc: Fix too large frame size warnings	2017-09-22 19:46:07 +02:00
Kconfig.kasan
Kconfig.kgdb
Kconfig.kmemcheck
Kconfig.ubsan
kfifo.c
klist.c
kobject.c
kobject_uevent.c	driver core: suppress sending MODALIAS in UNBIND uevents	2017-09-18 16:48:33 +02:00
kstrtox.c
kstrtox.h
lcm.c
libcrc32c.c
list_debug.c
list_sort.c
llist.c
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-rtmutex.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
lockref.c
lru_cache.c
Makefile	Merge branch 'zstd-minimal' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs	2017-09-14 17:30:49 -07:00
memory-notifier-error-inject.c
memweight.c
net_utils.c
netdev-notifier-error-inject.c
nlattr.c
nmi_backtrace.c
nodemask.c
notifier-error-inject.c
notifier-error-inject.h
of-reconfig-notifier-error-inject.c
oid_registry.c	lib/oid_registry.c: X.509: fix the buffer overflow in the utility function for OID string	2017-09-08 18:26:49 -07:00
once.c
parman.c
parser.c
pci_iomap.c
percpu-refcount.c
percpu_counter.c
percpu_ida.c
percpu_test.c
plist.c
pm-notifier-error-inject.c
prime_numbers.c
radix-tree.c	radix-tree: must check __radix_tree_preload() return value	2017-09-08 18:26:49 -07:00
random32.c
ratelimit.c	lib/ratelimit.c: use deferred printk() version	2017-10-03 17:54:26 -07:00
rational.c
rbtree.c	rbtree: add some additional comments for rebalancing cases	2017-09-08 18:26:48 -07:00
rbtree_test.c	lib/rbtree_test.c: support rb_root_cached	2017-09-08 18:26:48 -07:00
reciprocal_div.c
refcount.c
rhashtable.c	rhashtable: Documentation tweak	2017-09-19 15:18:33 -07:00
sbitmap.c
scatterlist.c
seq_buf.c
sg_pool.c
sg_split.c
sha1.c
show_mem.c
siphash.c
smp_processor_id.c
sort.c
stackdepot.c
stmp_device.c
string.c	lib/string.c: check for kmalloc() failure	2017-09-08 18:26:49 -07:00
string_helpers.c	mm: treewide: remove GFP_TEMPORARY allocation flag	2017-09-13 18:53:16 -07:00
strncpy_from_user.c
strnlen_user.c
swiotlb.c
syscall.c
test-kstrtox.c
test-string_helpers.c
test_bitmap.c	lib/test_bitmap.c: use ULL suffix for 64-bit constants	2017-09-13 18:53:15 -07:00
test_bpf.c
test_debug_virtual.c	lib: add test module for CONFIG_DEBUG_VIRTUAL	2017-09-08 18:26:49 -07:00
test_firmware.c
test_hash.c
test_hexdump.c
test_kasan.c
test_kmod.c	test_kmod: flip INT checks to be consistent	2017-09-08 18:26:50 -07:00
test_list_sort.c
test_module.c
test_parman.c
test_printf.c
test_rhashtable.c
test_siphash.c
test_sort.c
test_static_key_base.c
test_static_keys.c
test_sysctl.c
test_user_copy.c
test_uuid.c
textsearch.c
timerqueue.c
ts_bm.c
ts_fsm.c
ts_kmp.c
ubsan.c
ubsan.h
ucs2_string.c
usercopy.c
uuid.c
vsprintf.c
win_minmax.c
xxhash.c