/* * fixmap.h: compile-time virtual memory allocation * * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) 1998 Ingo Molnar * * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999 * x86_32 and x86_64 integration by Gustavo F. Padovan, February 2009 * Break out common bits to asm-generic by Mark Salter, November 2013 */ #ifndef __ASM_GENERIC_FIXMAP_H #define __ASM_GENERIC_FIXMAP_H #include #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT)) #define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT) #ifndef __ASSEMBLY__ /* * 'index to address' translation. If anyone tries to use the idx * directly without translation, we catch the bug with a NULL-deference * kernel oops. Illegal ranges of incoming indices are caught too. */ static __always_inline unsigned long fix_to_virt(const unsigned int idx) { BUILD_BUG_ON(idx >= __end_of_fixed_addresses); return __fix_to_virt(idx); } static inline unsigned long virt_to_fix(const unsigned long vaddr) { BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START); return __virt_to_fix(vaddr); } /* * Provide some reasonable defaults for page flags. * Not all architectures use all of these different types and some * architectures use different names. */ #ifndef FIXMAP_PAGE_NORMAL #define FIXMAP_PAGE_NORMAL PAGE_KERNEL #endif #if !defined(FIXMAP_PAGE_RO) && defined(PAGE_KERNEL_RO) #define FIXMAP_PAGE_RO PAGE_KERNEL_RO #endif #ifndef FIXMAP_PAGE_NOCACHE #define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NOCACHE #endif #ifndef FIXMAP_PAGE_IO #define FIXMAP_PAGE_IO PAGE_KERNEL_IO #endif #ifndef FIXMAP_PAGE_CLEAR #define FIXMAP_PAGE_CLEAR __pgprot(0) #endif #ifndef set_fixmap #define set_fixmap(idx, phys) \ __set_fixmap(idx, phys, FIXMAP_PAGE_NORMAL) #endif #ifndef clear_fixmap #define clear_fixmap(idx) \ __set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR) #endif /* Return a pointer with offset calculated */ #define __set_fixmap_offset(idx, phys, flags) \ ({ \ unsigned long ________addr; \ __set_fixmap(idx, phys, flags); \ ________addr = fix_to_virt(idx) + ((phys) & (PAGE_SIZE - 1)); \ ________addr; \ }) #define set_fixmap_offset(idx, phys) \ __set_fixmap_offset(idx, phys, FIXMAP_PAGE_NORMAL) /* * Some hardware wants to get fixmapped without caching. */ #define set_fixmap_nocache(idx, phys) \ __set_fixmap(idx, phys, FIXMAP_PAGE_NOCACHE) #define set_fixmap_offset_nocache(idx, phys) \ __set_fixmap_offset(idx, phys, FIXMAP_PAGE_NOCACHE) /* * Some fixmaps are for IO */ #define set_fixmap_io(idx, phys) \ __set_fixmap(idx, phys, FIXMAP_PAGE_IO) #define set_fixmap_offset_io(idx, phys) \ __set_fixmap_offset(idx, phys, FIXMAP_PAGE_IO) #endif /* __ASSEMBLY__ */ #endif /* __ASM_GENERIC_FIXMAP_H */ ext.git/commit/net?id=966d2b04e070bc040319aaebfec09e0144dc3341'>net/netlabel/netlabel_unlabeled.h
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authorDouglas Miller <dougmill@linux.vnet.ibm.com>2017-01-28 06:42:20 -0600
committerTejun Heo <tj@kernel.org>2017-01-28 07:49:42 -0500
commit966d2b04e070bc040319aaebfec09e0144dc3341 (patch)
tree4b96156e3d1dd4dfd6039b7c219c9dc4616da52d /net/netlabel/netlabel_unlabeled.h
parent1b1bc42c1692e9b62756323c675a44cb1a1f9dbd (diff)
percpu-refcount: fix reference leak during percpu-atomic transition
percpu_ref_tryget() and percpu_ref_tryget_live() should return "true" IFF they acquire a reference. But the return value from atomic_long_inc_not_zero() is a long and may have high bits set, e.g. PERCPU_COUNT_BIAS, and the return value of the tryget routines is bool so the reference may actually be acquired but the routines return "false" which results in a reference leak since the caller assumes it does not need to do a corresponding percpu_ref_put(). This was seen when performing CPU hotplug during I/O, as hangs in blk_mq_freeze_queue_wait where percpu_ref_kill (blk_mq_freeze_queue_start) raced with percpu_ref_tryget (blk_mq_timeout_work). Sample stack trace: __switch_to+0x2c0/0x450 __schedule+0x2f8/0x970 schedule+0x48/0xc0 blk_mq_freeze_queue_wait+0x94/0x120 blk_mq_queue_reinit_work+0xb8/0x180 blk_mq_queue_reinit_prepare+0x84/0xa0 cpuhp_invoke_callback+0x17c/0x600 cpuhp_up_callbacks+0x58/0x150 _cpu_up+0xf0/0x1c0 do_cpu_up+0x120/0x150 cpu_subsys_online+0x64/0xe0 device_online+0xb4/0x120 online_store+0xb4/0xc0 dev_attr_store+0x68/0xa0 sysfs_kf_write+0x80/0xb0 kernfs_fop_write+0x17c/0x250 __vfs_write+0x6c/0x1e0 vfs_write+0xd0/0x270 SyS_write+0x6c/0x110 system_call+0x38/0xe0 Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS, and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests. However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0 and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set. The fix is to make the tryget routines use an actual boolean internally instead of the atomic long result truncated to a int. Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751 Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com> Reviewed-by: Jens Axboe <axboe@fb.com> Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints") Cc: stable@vger.kernel.org # v3.18+
Diffstat (limited to 'net/netlabel/netlabel_unlabeled.h')