@@ -398,10 +398,11 @@ static efi_status_t
get_var_data(struct efivars *efivars, struct efi_variable *var)
{
efi_status_t status;
+ unsigned long flags;
- spin_lock(&efivars->lock);
+ spin_lock_irqsave(&efivars->lock, flags);
status = get_var_data_locked(efivars, var);
- spin_unlock(&efivars->lock);
+ spin_unlock_irqrestore(&efivars->lock, flags);
if (status != EFI_SUCCESS) {
printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
@@ -530,14 +531,14 @@ efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
return -EINVAL;
}
- spin_lock(&efivars->lock);
+ spin_lock_irq(&efivars->lock);
status = efivars->ops->set_variable(new_var->VariableName,
&new_var->VendorGuid,
new_var->Attributes,
new_var->DataSize,
new_var->Data);
- spin_unlock(&efivars->lock);
+ spin_unlock_irq(&efivars->lock);
if (status != EFI_SUCCESS) {
printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
@@ -646,7 +647,7 @@ static int efi_pstore_open(struct pstore_info *psi)
{
struct efivars *efivars = psi->data;
- spin_lock(&efivars->lock);
+ spin_lock_irq(&efivars->lock);
efivars->walk_entry = list_first_entry(&efivars->list,
struct efivar_entry, list);
return 0;
@@ -656,7 +657,7 @@ static int efi_pstore_close(struct pstore_info *psi)
{
struct efivars *efivars = psi->data;
- spin_unlock(&efivars->lock);
+ spin_unlock_irq(&efivars->lock);
return 0;
}
@@ -712,11 +713,12 @@ static int efi_pstore_write(enum pstore_type_id type,
int i, ret = 0;
u64 storage_space, remaining_space, max_variable_size;
efi_status_t status = EFI_NOT_FOUND;
+ unsigned long flags;
sprintf(stub_name, "dump-type%u-%u-", type, part);
sprintf(name, "%s%lu", stub_name, get_seconds());
- spin_lock(&efivars->lock);
+ spin_lock_irqsave(&efivars->lock, flags);
/*
* Check if there is a space enough to log.
@@ -728,7 +730,7 @@ static int efi_pstore_write(enum pstore_type_id type,
&remaining_space,
&max_variable_size);
if (status || remaining_space < size + DUMP_NAME_LEN * 2) {
- spin_unlock(&efivars->lock);
+ spin_unlock_irqrestore(&efivars->lock, flags);
*id = part;
return -ENOSPC;
}
@@ -769,7 +771,7 @@ static int efi_pstore_write(enum pstore_type_id type,
efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
size, psi->buf);
- spin_unlock(&efivars->lock);
+ spin_unlock_irqrestore(&efivars->lock, flags);
if (found)
efivar_unregister(found);
@@ -840,7 +842,7 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
return -EINVAL;
}
- spin_lock(&efivars->lock);
+ spin_lock_irq(&efivars->lock);
/*
* Does this variable already exist?
@@ -858,7 +860,7 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
}
}
if (found) {
- spin_unlock(&efivars->lock);
+ spin_unlock_irq(&efivars->lock);
return -EINVAL;
}
@@ -872,10 +874,10 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
if (status != EFI_SUCCESS) {
printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
status);
- spin_unlock(&efivars->lock);
+ spin_unlock_irq(&efivars->lock);
return -EIO;
}
- spin_unlock(&efivars->lock);
+ spin_unlock_irq(&efivars->lock);
/* Create the entry in sysfs. Locking is not required here */
status = efivar_create_sysfs_entry(efivars,
@@ -903,7 +905,7 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
- spin_lock(&efivars->lock);
+ spin_lock_irq(&efivars->lock);
/*
* Does this variable already exist?
@@ -921,7 +923,7 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
}
}
if (!found) {
- spin_unlock(&efivars->lock);
+ spin_unlock_irq(&efivars->lock);
return -EINVAL;
}
/* force the Attributes/DataSize to 0 to ensure deletion */
@@ -937,12 +939,12 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
if (status != EFI_SUCCESS) {
printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
status);
- spin_unlock(&efivars->lock);
+ spin_unlock_irq(&efivars->lock);
return -EIO;
}
list_del(&search_efivar->list);
/* We need to release this lock before unregistering. */
- spin_unlock(&efivars->lock);
+ spin_unlock_irq(&efivars->lock);
efivar_unregister(search_efivar);
/* It's dead Jim.... */
@@ -1050,9 +1052,9 @@ efivar_create_sysfs_entry(struct efivars *efivars,
kfree(short_name);
short_name = NULL;
- spin_lock(&efivars->lock);
+ spin_lock_irq(&efivars->lock);
list_add(&new_efivar->list, &efivars->list);
- spin_unlock(&efivars->lock);
+ spin_unlock_irq(&efivars->lock);
return 0;
}
@@ -1121,9 +1123,9 @@ void unregister_efivars(struct efivars *efivars)
struct efivar_entry *entry, *n;
list_for_each_entry_safe(entry, n, &efivars->list, list) {
- spin_lock(&efivars->lock);
+ spin_lock_irq(&efivars->lock);
list_del(&entry->list);
- spin_unlock(&efivars->lock);
+ spin_unlock_irq(&efivars->lock);
efivar_unregister(entry);
}
if (efivars->new_var)
This is a note to let you know that I have just added a patch titled efivars: Disable external interrupt while holding to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From d85a45658d6bcf69caae4311f2eb5f9d93c98f58 Mon Sep 17 00:00:00 2001 From: Seiji Aguchi <seiji.aguchi@hds.com> Date: Tue, 12 Feb 2013 12:59:07 -0800 Subject: [PATCH] efivars: Disable external interrupt while holding efivars->lock commit 81fa4e581d9283f7992a0d8c534bb141eb840a14 upstream. [Problem] There is a scenario which efi_pstore fails to log messages in a panic case. - CPUA holds an efi_var->lock in either efivarfs parts or efi_pstore with interrupt enabled. - CPUB panics and sends IPI to CPUA in smp_send_stop(). - CPUA stops with holding the lock. - CPUB kicks efi_pstore_write() via kmsg_dump(KSMG_DUMP_PANIC) but it returns without logging messages. [Patch Description] This patch disables an external interruption while holding efivars->lock as follows. In efi_pstore_write() and get_var_data(), spin_lock/spin_unlock is replaced by spin_lock_irqsave/spin_unlock_irqrestore because they may be called in an interrupt context. In other functions, they are replaced by spin_lock_irq/spin_unlock_irq. because they are all called from a process context. By applying this patch, we can avoid the problem above with a following senario. - CPUA holds an efi_var->lock with interrupt disabled. - CPUB panics and sends IPI to CPUA in smp_send_stop(). - CPUA receives the IPI after releasing the lock because it is disabling interrupt while holding the lock. - CPUB waits for one sec until CPUA releases the lock. - CPUB kicks efi_pstore_write() via kmsg_dump(KSMG_DUMP_PANIC) And it can hold the lock successfully. Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com> Acked-by: Mike Waychison <mikew@google.com> Acked-by: Matt Fleming <matt.fleming@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Cc: Ben Hutchings <ben@decadent.org.uk> [ luis: backport to 3.4, based on bwh's backport to 3.2: - Drop efivarfs changes - Adjust context - Drop change to efi_pstore_erase(), which is implemented using efi_pstore_write() here ] Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- drivers/firmware/efivars.c | 44 +++++++++++++++++++++++--------------------- 1 file changed, 23 insertions(+), 21 deletions(-) -- 1.8.1.2