--- /dev/null
+From 06a8566bcf5cf7db9843a82cde7a33c7bf3947d9 Mon Sep 17 00:00:00 2001
+From: Lv Zheng <lv.zheng@intel.com>
+Date: Fri, 13 Sep 2013 13:13:23 +0800
+Subject: ACPI / IPMI: Fix atomic context requirement of ipmi_msg_handler()
+
+From: Lv Zheng <lv.zheng@intel.com>
+
+commit 06a8566bcf5cf7db9843a82cde7a33c7bf3947d9 upstream.
+
+This patch fixes the issues indicated by the test results that
+ipmi_msg_handler() is invoked in atomic context.
+
+BUG: scheduling while atomic: kipmi0/18933/0x10000100
+Modules linked in: ipmi_si acpi_ipmi ...
+CPU: 3 PID: 18933 Comm: kipmi0 Tainted: G AW 3.10.0-rc7+ #2
+Hardware name: QCI QSSC-S4R/QSSC-S4R, BIOS QSSC-S4R.QCI.01.00.0027.070120100606 07/01/2010
+ ffff8838245eea00 ffff88103fc63c98 ffffffff814c4a1e ffff88103fc63ca8
+ ffffffff814bfbab ffff88103fc63d28 ffffffff814c73e0 ffff88103933cbd4
+ 0000000000000096 ffff88103fc63ce8 ffff88102f618000 ffff881035c01fd8
+Call Trace:
+ <IRQ> [<ffffffff814c4a1e>] dump_stack+0x19/0x1b
+ [<ffffffff814bfbab>] __schedule_bug+0x46/0x54
+ [<ffffffff814c73e0>] __schedule+0x83/0x59c
+ [<ffffffff81058853>] __cond_resched+0x22/0x2d
+ [<ffffffff814c794b>] _cond_resched+0x14/0x1d
+ [<ffffffff814c6d82>] mutex_lock+0x11/0x32
+ [<ffffffff8101e1e9>] ? __default_send_IPI_dest_field.constprop.0+0x53/0x58
+ [<ffffffffa09e3f9c>] ipmi_msg_handler+0x23/0x166 [ipmi_si]
+ [<ffffffff812bf6e4>] deliver_response+0x55/0x5a
+ [<ffffffff812c0fd4>] handle_new_recv_msgs+0xb67/0xc65
+ [<ffffffff81007ad1>] ? read_tsc+0x9/0x19
+ [<ffffffff814c8620>] ? _raw_spin_lock_irq+0xa/0xc
+ [<ffffffffa09e1128>] ipmi_thread+0x5c/0x146 [ipmi_si]
+ ...
+
+Also Tony Camuso says:
+
+ We were getting occasional "Scheduling while atomic" call traces
+ during boot on some systems. Problem was first seen on a Cisco C210
+ but we were able to reproduce it on a Cisco c220m3. Setting
+ CONFIG_LOCKDEP and LOCKDEP_SUPPORT to 'y' exposed a lockdep around
+ tx_msg_lock in acpi_ipmi.c struct acpi_ipmi_device.
+
+ =================================
+ [ INFO: inconsistent lock state ]
+ 2.6.32-415.el6.x86_64-debug-splck #1
+ ---------------------------------
+ inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
+ ksoftirqd/3/17 [HC0[0]:SC1[1]:HE1:SE0] takes:
+ (&ipmi_device->tx_msg_lock){+.?...}, at: [<ffffffff81337a27>] ipmi_msg_handler+0x71/0x126
+ {SOFTIRQ-ON-W} state was registered at:
+ [<ffffffff810ba11c>] __lock_acquire+0x63c/0x1570
+ [<ffffffff810bb0f4>] lock_acquire+0xa4/0x120
+ [<ffffffff815581cc>] __mutex_lock_common+0x4c/0x400
+ [<ffffffff815586ea>] mutex_lock_nested+0x4a/0x60
+ [<ffffffff8133789d>] acpi_ipmi_space_handler+0x11b/0x234
+ [<ffffffff81321c62>] acpi_ev_address_space_dispatch+0x170/0x1be
+
+The fix implemented by this change has been tested by Tony:
+
+ Tested the patch in a boot loop with lockdep debug enabled and never
+ saw the problem in over 400 reboots.
+
+Reported-and-tested-by: Tony Camuso <tcamuso@redhat.com>
+Signed-off-by: Lv Zheng <lv.zheng@intel.com>
+Reviewed-by: Huang Ying <ying.huang@intel.com>
+Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+Cc: Jonghwan Choi <jhbird.choi@samsung.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/acpi/acpi_ipmi.c | 24 ++++++++++++++----------
+ 1 file changed, 14 insertions(+), 10 deletions(-)
+
+--- a/drivers/acpi/acpi_ipmi.c
++++ b/drivers/acpi/acpi_ipmi.c
+@@ -39,6 +39,7 @@
+ #include <linux/ipmi.h>
+ #include <linux/device.h>
+ #include <linux/pnp.h>
++#include <linux/spinlock.h>
+
+ MODULE_AUTHOR("Zhao Yakui");
+ MODULE_DESCRIPTION("ACPI IPMI Opregion driver");
+@@ -57,7 +58,7 @@ struct acpi_ipmi_device {
+ struct list_head head;
+ /* the IPMI request message list */
+ struct list_head tx_msg_list;
+- struct mutex tx_msg_lock;
++ spinlock_t tx_msg_lock;
+ acpi_handle handle;
+ struct pnp_dev *pnp_dev;
+ ipmi_user_t user_interface;
+@@ -147,6 +148,7 @@ static void acpi_format_ipmi_msg(struct
+ struct kernel_ipmi_msg *msg;
+ struct acpi_ipmi_buffer *buffer;
+ struct acpi_ipmi_device *device;
++ unsigned long flags;
+
+ msg = &tx_msg->tx_message;
+ /*
+@@ -177,10 +179,10 @@ static void acpi_format_ipmi_msg(struct
+
+ /* Get the msgid */
+ device = tx_msg->device;
+- mutex_lock(&device->tx_msg_lock);
++ spin_lock_irqsave(&device->tx_msg_lock, flags);
+ device->curr_msgid++;
+ tx_msg->tx_msgid = device->curr_msgid;
+- mutex_unlock(&device->tx_msg_lock);
++ spin_unlock_irqrestore(&device->tx_msg_lock, flags);
+ }
+
+ static void acpi_format_ipmi_response(struct acpi_ipmi_msg *msg,
+@@ -242,6 +244,7 @@ static void ipmi_msg_handler(struct ipmi
+ int msg_found = 0;
+ struct acpi_ipmi_msg *tx_msg;
+ struct pnp_dev *pnp_dev = ipmi_device->pnp_dev;
++ unsigned long flags;
+
+ if (msg->user != ipmi_device->user_interface) {
+ dev_warn(&pnp_dev->dev, "Unexpected response is returned. "
+@@ -250,7 +253,7 @@ static void ipmi_msg_handler(struct ipmi
+ ipmi_free_recv_msg(msg);
+ return;
+ }
+- mutex_lock(&ipmi_device->tx_msg_lock);
++ spin_lock_irqsave(&ipmi_device->tx_msg_lock, flags);
+ list_for_each_entry(tx_msg, &ipmi_device->tx_msg_list, head) {
+ if (msg->msgid == tx_msg->tx_msgid) {
+ msg_found = 1;
+@@ -258,7 +261,7 @@ static void ipmi_msg_handler(struct ipmi
+ }
+ }
+
+- mutex_unlock(&ipmi_device->tx_msg_lock);
++ spin_unlock_irqrestore(&ipmi_device->tx_msg_lock, flags);
+ if (!msg_found) {
+ dev_warn(&pnp_dev->dev, "Unexpected response (msg id %ld) is "
+ "returned.\n", msg->msgid);
+@@ -378,6 +381,7 @@ acpi_ipmi_space_handler(u32 function, ac
+ struct acpi_ipmi_device *ipmi_device = handler_context;
+ int err, rem_time;
+ acpi_status status;
++ unsigned long flags;
+ /*
+ * IPMI opregion message.
+ * IPMI message is firstly written to the BMC and system software
+@@ -395,9 +399,9 @@ acpi_ipmi_space_handler(u32 function, ac
+ return AE_NO_MEMORY;
+
+ acpi_format_ipmi_msg(tx_msg, address, value);
+- mutex_lock(&ipmi_device->tx_msg_lock);
++ spin_lock_irqsave(&ipmi_device->tx_msg_lock, flags);
+ list_add_tail(&tx_msg->head, &ipmi_device->tx_msg_list);
+- mutex_unlock(&ipmi_device->tx_msg_lock);
++ spin_unlock_irqrestore(&ipmi_device->tx_msg_lock, flags);
+ err = ipmi_request_settime(ipmi_device->user_interface,
+ &tx_msg->addr,
+ tx_msg->tx_msgid,
+@@ -413,9 +417,9 @@ acpi_ipmi_space_handler(u32 function, ac
+ status = AE_OK;
+
+ end_label:
+- mutex_lock(&ipmi_device->tx_msg_lock);
++ spin_lock_irqsave(&ipmi_device->tx_msg_lock, flags);
+ list_del(&tx_msg->head);
+- mutex_unlock(&ipmi_device->tx_msg_lock);
++ spin_unlock_irqrestore(&ipmi_device->tx_msg_lock, flags);
+ kfree(tx_msg);
+ return status;
+ }
+@@ -457,7 +461,7 @@ static void acpi_add_ipmi_device(struct
+
+ INIT_LIST_HEAD(&ipmi_device->head);
+
+- mutex_init(&ipmi_device->tx_msg_lock);
++ spin_lock_init(&ipmi_device->tx_msg_lock);
+ INIT_LIST_HEAD(&ipmi_device->tx_msg_list);
+ ipmi_install_space_handler(ipmi_device);
+
projects / thirdparty / kernel / stable-queue.git / commitdiff
