4.19-stable patches

added patches:
	revert-revert-char-random-silence-a-lockdep-splat-with-printk.patch

diff --git a/queue-4.19/revert-revert-char-random-silence-a-lockdep-splat-with-printk.patch b/queue-4.19/revert-revert-char-random-silence-a-lockdep-splat-with-printk.patch
new file mode 100644 (file)
index 0000000..9ca95ba
--- /dev/null
+++ b/queue-4.19/revert-revert-char-random-silence-a-lockdep-splat-with-printk.patch
@@ -0,0 +1,200 @@
+From Jason@zx2c4.com  Sun Jul 24 16:58:00 2022
+From: "Jason A. Donenfeld" <Jason@zx2c4.com>
+Date: Sun, 24 Jul 2022 16:51:48 +0200
+Subject: Revert "Revert "char/random: silence a lockdep splat with printk()""
+To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, gregkh@linuxfoundation.org
+Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>, Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>, Qian Cai <cai@lca.pw>, Lech Perczak <l.perczak@camlintechnologies.com>, Theodore Ts'o <tytso@mit.edu>, Sasha Levin <sashal@kernel.org>, Petr Mladek <pmladek@suse.com>, John Ogness <john.ogness@linutronix.de>, kernel test robot <oliver.sang@intel.com>
+Message-ID: <20220724145148.664623-1-Jason@zx2c4.com>
+
+From: "Jason A. Donenfeld" <Jason@zx2c4.com>
+
+In 2019, Sergey fixed a lockdep splat with 15341b1dd409 ("char/random:
+silence a lockdep splat with printk()"), but that got reverted soon
+after from 4.19 because back then it apparently caused various problems.
+But the issue it was fixing is still there, and more generally, many
+patches turning printk() into printk_deferred() have landed since,
+making me suspect it's okay to try this out again.
+
+This should fix the following deadlock found by the kernel test robot:
+
+[   18.287691] WARNING: possible circular locking dependency detected
+[   18.287692] 4.19.248-00165-g3d1f971aa81f #1 Not tainted
+[   18.287693] ------------------------------------------------------
+[   18.287712] stop/202 is trying to acquire lock:
+[   18.287713] (ptrval) (console_owner){..-.}, at: console_unlock (??:?)
+[   18.287717]
+[   18.287718] but task is already holding lock:
+[   18.287718] (ptrval) (&(&port->lock)->rlock){-...}, at: pty_write (pty.c:?)
+[   18.287722]
+[   18.287722] which lock already depends on the new lock.
+[   18.287723]
+[   18.287724]
+[   18.287725] the existing dependency chain (in reverse order) is:
+[   18.287725]
+[   18.287726] -> #2 (&(&port->lock)->rlock){-...}:
+[   18.287729] validate_chain+0x84a/0xe00
+[   18.287729] __lock_acquire (lockdep.c:?)
+[   18.287730] lock_acquire (??:?)
+[   18.287731] _raw_spin_lock_irqsave (??:?)
+[   18.287732] tty_port_tty_get (??:?)
+[   18.287733] tty_port_default_wakeup (tty_port.c:?)
+[   18.287734] tty_port_tty_wakeup (??:?)
+[   18.287734] uart_write_wakeup (??:?)
+[   18.287735] serial8250_tx_chars (??:?)
+[   18.287736] serial8250_handle_irq (??:?)
+[   18.287737] serial8250_default_handle_irq (8250_port.c:?)
+[   18.287738] serial8250_interrupt (8250_core.c:?)
+[   18.287738] __handle_irq_event_percpu (??:?)
+[   18.287739] handle_irq_event_percpu (??:?)
+[   18.287740] handle_irq_event (??:?)
+[   18.287741] handle_edge_irq (??:?)
+[   18.287742] handle_irq (??:?)
+[   18.287742] do_IRQ (??:?)
+[   18.287743] common_interrupt (entry_32.o:?)
+[   18.287744] _raw_spin_unlock_irqrestore (??:?)
+[   18.287745] uart_write (serial_core.c:?)
+[   18.287746] process_output_block (n_tty.c:?)
+[   18.287747] n_tty_write (n_tty.c:?)
+[   18.287747] tty_write (tty_io.c:?)
+[   18.287748] __vfs_write (??:?)
+[   18.287749] vfs_write (??:?)
+[   18.287750] ksys_write (??:?)
+[   18.287750] sys_write (??:?)
+[   18.287751] do_fast_syscall_32 (??:?)
+[   18.287752] entry_SYSENTER_32 (??:?)
+[   18.287752]
+[   18.287753] -> #1 (&port_lock_key){-.-.}:
+[   18.287756]
+[   18.287756] -> #0 (console_owner){..-.}:
+[   18.287759] check_prevs_add (lockdep.c:?)
+[   18.287760] validate_chain+0x84a/0xe00
+[   18.287761] __lock_acquire (lockdep.c:?)
+[   18.287761] lock_acquire (??:?)
+[   18.287762] console_unlock (??:?)
+[   18.287763] vprintk_emit (??:?)
+[   18.287764] vprintk_default (??:?)
+[   18.287764] vprintk_func (??:?)
+[   18.287765] printk (??:?)
+[   18.287766] get_random_u32 (??:?)
+[   18.287767] shuffle_freelist (slub.c:?)
+[   18.287767] allocate_slab (slub.c:?)
+[   18.287768] new_slab (slub.c:?)
+[   18.287769] ___slab_alloc+0x6d0/0xb20
+[   18.287770] __slab_alloc+0xd6/0x2e0
+[   18.287770] __kmalloc (??:?)
+[   18.287771] tty_buffer_alloc (tty_buffer.c:?)
+[   18.287772] __tty_buffer_request_room (tty_buffer.c:?)
+[   18.287773] tty_insert_flip_string_fixed_flag (??:?)
+[   18.287774] pty_write (pty.c:?)
+[   18.287775] process_output_block (n_tty.c:?)
+[   18.287776] n_tty_write (n_tty.c:?)
+[   18.287777] tty_write (tty_io.c:?)
+[   18.287778] __vfs_write (??:?)
+[   18.287779] vfs_write (??:?)
+[   18.287780] ksys_write (??:?)
+[   18.287780] sys_write (??:?)
+[   18.287781] do_fast_syscall_32 (??:?)
+[   18.287782] entry_SYSENTER_32 (??:?)
+[   18.287783]
+[   18.287783] other info that might help us debug this:
+[   18.287784]
+[   18.287785] Chain exists of:
+[   18.287785]   console_owner --> &port_lock_key --> &(&port->lock)->rlock
+[   18.287789]
+[   18.287790]  Possible unsafe locking scenario:
+[   18.287790]
+[   18.287791]        CPU0                    CPU1
+[   18.287792]        ----                    ----
+[   18.287792]   lock(&(&port->lock)->rlock);
+[   18.287794]                                lock(&port_lock_key);
+[   18.287814]                                lock(&(&port->lock)->rlock);
+[   18.287815]   lock(console_owner);
+[   18.287817]
+[   18.287818]  *** DEADLOCK ***
+[   18.287818]
+[   18.287819] 6 locks held by stop/202:
+[   18.287820] #0: (ptrval) (&tty->ldisc_sem){++++}, at: ldsem_down_read (??:?)
+[   18.287823] #1: (ptrval) (&tty->atomic_write_lock){+.+.}, at: tty_write_lock (tty_io.c:?)
+[   18.287826] #2: (ptrval) (&o_tty->termios_rwsem/1){++++}, at: n_tty_write (n_tty.c:?)
+[   18.287830] #3: (ptrval) (&ldata->output_lock){+.+.}, at: process_output_block (n_tty.c:?)
+[   18.287834] #4: (ptrval) (&(&port->lock)->rlock){-...}, at: pty_write (pty.c:?)
+[   18.287838] #5: (ptrval) (console_lock){+.+.}, at: console_trylock_spinning (printk.c:?)
+[   18.287841]
+[   18.287842] stack backtrace:
+[   18.287843] CPU: 0 PID: 202 Comm: stop Not tainted 4.19.248-00165-g3d1f971aa81f #1
+[   18.287843] Call Trace:
+[   18.287844] dump_stack (??:?)
+[   18.287845] print_circular_bug.cold+0x78/0x8b
+[   18.287846] check_prev_add+0x66a/0xd20
+[   18.287847] check_prevs_add (lockdep.c:?)
+[   18.287848] validate_chain+0x84a/0xe00
+[   18.287848] __lock_acquire (lockdep.c:?)
+[   18.287849] lock_acquire (??:?)
+[   18.287850] ? console_unlock (??:?)
+[   18.287851] console_unlock (??:?)
+[   18.287851] ? console_unlock (??:?)
+[   18.287852] ? native_save_fl (??:?)
+[   18.287853] vprintk_emit (??:?)
+[   18.287854] vprintk_default (??:?)
+[   18.287855] vprintk_func (??:?)
+[   18.287855] printk (??:?)
+[   18.287856] get_random_u32 (??:?)
+[   18.287857] ? shuffle_freelist (slub.c:?)
+[   18.287858] shuffle_freelist (slub.c:?)
+[   18.287858] ? page_address (??:?)
+[   18.287859] allocate_slab (slub.c:?)
+[   18.287860] new_slab (slub.c:?)
+[   18.287861] ? pvclock_clocksource_read (??:?)
+[   18.287862] ___slab_alloc+0x6d0/0xb20
+[   18.287862] ? kvm_sched_clock_read (kvmclock.c:?)
+[   18.287863] ? __slab_alloc+0xbc/0x2e0
+[   18.287864] ? native_wbinvd (paravirt.c:?)
+[   18.287865] __slab_alloc+0xd6/0x2e0
+[   18.287865] __kmalloc (??:?)
+[   18.287866] ? __lock_acquire (lockdep.c:?)
+[   18.287867] ? tty_buffer_alloc (tty_buffer.c:?)
+[   18.287868] tty_buffer_alloc (tty_buffer.c:?)
+[   18.287869] __tty_buffer_request_room (tty_buffer.c:?)
+[   18.287869] tty_insert_flip_string_fixed_flag (??:?)
+[   18.287870] pty_write (pty.c:?)
+[   18.287871] process_output_block (n_tty.c:?)
+[   18.287872] n_tty_write (n_tty.c:?)
+[   18.287873] ? print_dl_stats (??:?)
+[   18.287874] ? n_tty_ioctl (n_tty.c:?)
+[   18.287874] tty_write (tty_io.c:?)
+[   18.287875] ? n_tty_ioctl (n_tty.c:?)
+[   18.287876] ? tty_write_unlock (tty_io.c:?)
+[   18.287877] __vfs_write (??:?)
+[   18.287877] vfs_write (??:?)
+[   18.287878] ? __fget_light (file.c:?)
+[   18.287879] ksys_write (??:?)
+
+Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
+Cc: Qian Cai <cai@lca.pw>
+Cc: Lech Perczak <l.perczak@camlintechnologies.com>
+Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+Cc: Theodore Ts'o <tytso@mit.edu>
+Cc: Sasha Levin <sashal@kernel.org>
+Cc: Petr Mladek <pmladek@suse.com>
+Cc: John Ogness <john.ogness@linutronix.de>
+Reported-by: kernel test robot <oliver.sang@intel.com>
+Link: https://lore.kernel.org/lkml/Ytz+lo4zRQYG3JUR@xsang-OptiPlex-9020
+Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/char/random.c |    4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/drivers/char/random.c
++++ b/drivers/char/random.c
+@@ -183,8 +183,8 @@ static void __cold process_random_ready_
+ 
+ #define warn_unseeded_randomness() \
+       if (IS_ENABLED(CONFIG_WARN_ALL_UNSEEDED_RANDOM) && !crng_ready()) \
+-              pr_notice("%s called from %pS with crng_init=%d\n", \
+-                        __func__, (void *)_RET_IP_, crng_init)
++              printk_deferred(KERN_NOTICE "random: %s called from %pS with crng_init=%d\n", \
++                              __func__, (void *)_RET_IP_, crng_init)
+ 
+ 
+ /*********************************************************************

diff --git a/queue-4.19/series b/queue-4.19/series
index 393536c504578aba1bac15c15448c782d164bede..04f0156e49573776298bc774210ba84dc806ebc0 100644 (file)
--- a/queue-4.19/series
+++ b/queue-4.19/series
@@ -30,3 +30,4 @@ tcp-fix-a-data-race-around-sysctl_tcp_retrans_collap.patch
 tcp-fix-a-data-race-around-sysctl_tcp_stdurg.patch
 tcp-fix-a-data-race-around-sysctl_tcp_rfc1337.patch
 tcp-fix-data-races-around-sysctl_tcp_max_reordering.patch
+revert-revert-char-random-silence-a-lockdep-splat-with-printk.patch