漏洞信息
# ACPI: PPTT: 解决在没有PPTT时避免在原子上下文中休眠的问题
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漏洞标题
ACPI: PPTT: Fix to avoid sleep in the atomic context when PPTT is absent
漏洞描述信息
In the Linux kernel, the following vulnerability has been resolved:
ACPI: PPTT: Fix to avoid sleep in the atomic context when PPTT is absent
Commit 0c80f9e165f8 ("ACPI: PPTT: Leave the table mapped for the runtime usage")
enabled to map PPTT once on the first invocation of acpi_get_pptt() and
never unmapped the same allowing it to be used at runtime with out the
hassle of mapping and unmapping the table. This was needed to fetch LLC
information from the PPTT in the cpuhotplug path which is executed in
the atomic context as the acpi_get_table() might sleep waiting for a
mutex.
However it missed to handle the case when there is no PPTT on the system
which results in acpi_get_pptt() being called from all the secondary
CPUs attempting to fetch the LLC information in the atomic context
without knowing the absence of PPTT resulting in the splat like below:
| BUG: sleeping function called from invalid context at kernel/locking/semaphore.c:164
| in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 0, name: swapper/1
| preempt_count: 1, expected: 0
| RCU nest depth: 0, expected: 0
| no locks held by swapper/1/0.
| irq event stamp: 0
| hardirqs last enabled at (0): 0x0
| hardirqs last disabled at (0): copy_process+0x61c/0x1b40
| softirqs last enabled at (0): copy_process+0x61c/0x1b40
| softirqs last disabled at (0): 0x0
| CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.3.0-rc1 #1
| Call trace:
| dump_backtrace+0xac/0x138
| show_stack+0x30/0x48
| dump_stack_lvl+0x60/0xb0
| dump_stack+0x18/0x28
| __might_resched+0x160/0x270
| __might_sleep+0x58/0xb0
| down_timeout+0x34/0x98
| acpi_os_wait_semaphore+0x7c/0xc0
| acpi_ut_acquire_mutex+0x58/0x108
| acpi_get_table+0x40/0xe8
| acpi_get_pptt+0x48/0xa0
| acpi_get_cache_info+0x38/0x140
| init_cache_level+0xf4/0x118
| detect_cache_attributes+0x2e4/0x640
| update_siblings_masks+0x3c/0x330
| store_cpu_topology+0x88/0xf0
| secondary_start_kernel+0xd0/0x168
| __secondary_switched+0xb8/0xc0
Update acpi_get_pptt() to consider the fact that PPTT is once checked and
is not available on the system and return NULL avoiding any attempts to
fetch PPTT and thereby avoiding any possible sleep waiting for a mutex
in the atomic context.
CVSS信息
N/A
漏洞类别
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漏洞标题
Linux kernel 安全漏洞
漏洞描述信息
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于在原子上下文中处理PPTT表时可能导致睡眠。
CVSS信息
N/A
漏洞类别
其他
