This is a note to let you know that I've just added the patch titled
rtc: rx8010: change lock mechanism
to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: rtc-rx8010-change-lock-mechanism.patch and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Sun Nov 19 11:32:28 CET 2017
From: Fabien Lahoudere fabien.lahoudere@collabora.co.uk Date: Tue, 20 Dec 2016 09:42:44 +0100 Subject: rtc: rx8010: change lock mechanism
From: Fabien Lahoudere fabien.lahoudere@collabora.co.uk
[ Upstream commit 666b5d1e9f8762300a410f9548b6e370d71dd382 ]
Remove spinlock and use the "rtc->ops_lock" from RTC subsystem instead. spin_lock_irqsave() is not needed here because we do not have hard IRQs.
This patch fixes the following issue:
root@GE004097290448 b850v3:~# hwclock --systohc root@GE004097290448 b850v3:~# hwclock --systohc root@GE004097290448 b850v3:~# hwclock --systohc root@GE004097290448 b850v3:~# hwclock --systohc root@GE004097290448 b850v3:~# hwclock --systohc [ 82.108175] BUG: spinlock wrong CPU on CPU#0, hwclock/855 [ 82.113660] lock: 0xedb4899c, .magic: dead4ead, .owner: hwclock/855, .owner_cpu: 1 [ 82.121329] CPU: 0 PID: 855 Comm: hwclock Not tainted 4.8.0-00042-g09d5410-dirty #20 [ 82.129078] Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree) [ 82.135609] Backtrace: [ 82.138090] [<8010d378>] (dump_backtrace) from [<8010d5c0>] (show_stack+0x20/0x24) [ 82.145664] r7:ec936000 r6:600a0013 r5:00000000 r4:81031680 [ 82.151402] [<8010d5a0>] (show_stack) from [<80401518>] (dump_stack+0xb4/0xe8) [ 82.158636] [<80401464>] (dump_stack) from [<8017b8b0>] (spin_dump+0x84/0xcc) [ 82.165775] r10:00000000 r9:ec936000 r8:81056090 r7:600a0013 r6:edb4899c r5:edb4899c [ 82.173691] r4:e5033e00 r3:00000000 [ 82.177308] [<8017b82c>] (spin_dump) from [<8017bcb0>] (do_raw_spin_unlock+0x108/0x130) [ 82.185314] r5:edb4899c r4:edb4899c [ 82.188938] [<8017bba8>] (do_raw_spin_unlock) from [<8094b93c>] (_raw_spin_unlock_irqrestore+0x34/0x54) [ 82.198333] r5:edb4899c r4:600a0013 [ 82.201953] [<8094b908>] (_raw_spin_unlock_irqrestore) from [<8065b090>] (rx8010_set_time+0x14c/0x188) [ 82.211261] r5:00000020 r4:edb48990 [ 82.214882] [<8065af44>] (rx8010_set_time) from [<80653fe4>] (rtc_set_time+0x70/0x104) [ 82.222801] r7:00000051 r6:edb39da0 r5:edb39c00 r4:ec937e8c [ 82.228535] [<80653f74>] (rtc_set_time) from [<80655774>] (rtc_dev_ioctl+0x3c4/0x674) [ 82.236368] r7:00000051 r6:7ecf1b74 r5:00000000 r4:edb39c00 [ 82.242106] [<806553b0>] (rtc_dev_ioctl) from [<80284034>] (do_vfs_ioctl+0xa4/0xa6c) [ 82.249851] r8:00000003 r7:80284a40 r6:ed1e9c80 r5:edb44e60 r4:7ecf1b74 [ 82.256642] [<80283f90>] (do_vfs_ioctl) from [<80284a40>] (SyS_ioctl+0x44/0x6c) [ 82.263953] r10:00000000 r9:ec936000 r8:7ecf1b74 r7:4024700a r6:ed1e9c80 r5:00000003 [ 82.271869] r4:ed1e9c80 [ 82.274432] [<802849fc>] (SyS_ioctl) from [<80108520>] (ret_fast_syscall+0x0/0x1c) [ 82.282005] r9:ec936000 r8:801086c4 r7:00000036 r6:00000000 r5:00000003 r4:0008e1bc root@GE004097290448 b850v3:~# Message from syslogd@GE004097290448 at Dec 3 11:17:08 ... kernel:[ 82.108175] BUG: spinlock wrong CPU on CPU#0, hwclock/855
Message from syslogd@GE004097290448 at Dec 3 11:17:08 ... kernel:[ 82.113660] lock: 0xedb4899c, .magic: dead4ead, .owner: hwclock/855, .owner_cpu: 1 hwclock --systohc root@GE004097290448 b850v3:~#
Signed-off-by: Fabien Lahoudere fabien.lahoudere@collabora.co.uk Signed-off-by: Alexandre Belloni alexandre.belloni@free-electrons.com Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/rtc/rtc-rx8010.c | 24 +++--------------------- 1 file changed, 3 insertions(+), 21 deletions(-)
--- a/drivers/rtc/rtc-rx8010.c +++ b/drivers/rtc/rtc-rx8010.c @@ -63,7 +63,6 @@ struct rx8010_data { struct i2c_client *client; struct rtc_device *rtc; u8 ctrlreg; - spinlock_t flags_lock; };
static irqreturn_t rx8010_irq_1_handler(int irq, void *dev_id) @@ -72,12 +71,12 @@ static irqreturn_t rx8010_irq_1_handler( struct rx8010_data *rx8010 = i2c_get_clientdata(client); int flagreg;
- spin_lock(&rx8010->flags_lock); + mutex_lock(&rx8010->rtc->ops_lock);
flagreg = i2c_smbus_read_byte_data(client, RX8010_FLAG);
if (flagreg <= 0) { - spin_unlock(&rx8010->flags_lock); + mutex_unlock(&rx8010->rtc->ops_lock); return IRQ_NONE; }
@@ -101,7 +100,7 @@ static irqreturn_t rx8010_irq_1_handler(
i2c_smbus_write_byte_data(client, RX8010_FLAG, flagreg);
- spin_unlock(&rx8010->flags_lock); + mutex_unlock(&rx8010->rtc->ops_lock); return IRQ_HANDLED; }
@@ -143,7 +142,6 @@ static int rx8010_set_time(struct device u8 date[7]; int ctrl, flagreg; int ret; - unsigned long irqflags;
if ((dt->tm_year < 100) || (dt->tm_year > 199)) return -EINVAL; @@ -181,11 +179,8 @@ static int rx8010_set_time(struct device if (ret < 0) return ret;
- spin_lock_irqsave(&rx8010->flags_lock, irqflags); - flagreg = i2c_smbus_read_byte_data(rx8010->client, RX8010_FLAG); if (flagreg < 0) { - spin_unlock_irqrestore(&rx8010->flags_lock, irqflags); return flagreg; }
@@ -193,8 +188,6 @@ static int rx8010_set_time(struct device ret = i2c_smbus_write_byte_data(rx8010->client, RX8010_FLAG, flagreg & ~RX8010_FLAG_VLF);
- spin_unlock_irqrestore(&rx8010->flags_lock, irqflags); - return 0; }
@@ -288,12 +281,9 @@ static int rx8010_set_alarm(struct devic u8 alarmvals[3]; int extreg, flagreg; int err; - unsigned long irqflags;
- spin_lock_irqsave(&rx8010->flags_lock, irqflags); flagreg = i2c_smbus_read_byte_data(client, RX8010_FLAG); if (flagreg < 0) { - spin_unlock_irqrestore(&rx8010->flags_lock, irqflags); return flagreg; }
@@ -302,14 +292,12 @@ static int rx8010_set_alarm(struct devic err = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL, rx8010->ctrlreg); if (err < 0) { - spin_unlock_irqrestore(&rx8010->flags_lock, irqflags); return err; } }
flagreg &= ~RX8010_FLAG_AF; err = i2c_smbus_write_byte_data(rx8010->client, RX8010_FLAG, flagreg); - spin_unlock_irqrestore(&rx8010->flags_lock, irqflags); if (err < 0) return err;
@@ -404,7 +392,6 @@ static int rx8010_ioctl(struct device *d struct rx8010_data *rx8010 = dev_get_drvdata(dev); int ret, tmp; int flagreg; - unsigned long irqflags;
switch (cmd) { case RTC_VL_READ: @@ -419,16 +406,13 @@ static int rx8010_ioctl(struct device *d return 0;
case RTC_VL_CLR: - spin_lock_irqsave(&rx8010->flags_lock, irqflags); flagreg = i2c_smbus_read_byte_data(rx8010->client, RX8010_FLAG); if (flagreg < 0) { - spin_unlock_irqrestore(&rx8010->flags_lock, irqflags); return flagreg; }
flagreg &= ~RX8010_FLAG_VLF; ret = i2c_smbus_write_byte_data(client, RX8010_FLAG, flagreg); - spin_unlock_irqrestore(&rx8010->flags_lock, irqflags); if (ret < 0) return ret;
@@ -466,8 +450,6 @@ static int rx8010_probe(struct i2c_clien rx8010->client = client; i2c_set_clientdata(client, rx8010);
- spin_lock_init(&rx8010->flags_lock); - err = rx8010_init_client(client); if (err) return err;
Patches currently in stable-queue which might be from fabien.lahoudere@collabora.co.uk are
queue-4.9/rtc-rx8010-change-lock-mechanism.patch