/* * Copyright (c) 2000-2005 Silicon Graphics, Inc. * All Rights Reserved. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation. * * This program is distributed in the hope that it would be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #ifndef __XFS_SUPPORT_KMEM_H__ #define __XFS_SUPPORT_KMEM_H__ #include #include #include #include /* * General memory allocation interfaces */ typedef unsigned __bitwise xfs_km_flags_t; #define KM_SLEEP ((__force xfs_km_flags_t)0x0001u) #define KM_NOSLEEP ((__force xfs_km_flags_t)0x0002u) #define KM_NOFS ((__force xfs_km_flags_t)0x0004u) #define KM_MAYFAIL ((__force xfs_km_flags_t)0x0008u) #define KM_ZERO ((__force xfs_km_flags_t)0x0010u) /* * We use a special process flag to avoid recursive callbacks into * the filesystem during transactions. We will also issue our own * warnings, so we explicitly skip any generic ones (silly of us). */ static inline gfp_t kmem_flags_convert(xfs_km_flags_t flags) { gfp_t lflags; BUG_ON(flags & ~(KM_SLEEP|KM_NOSLEEP|KM_NOFS|KM_MAYFAIL|KM_ZERO)); if (flags & KM_NOSLEEP) { lflags = GFP_ATOMIC | __GFP_NOWARN; } else { lflags = GFP_KERNEL | __GFP_NOWARN; if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS)) lflags &= ~__GFP_FS; } if (flags & KM_ZERO) lflags |= __GFP_ZERO; return lflags; } extern void *kmem_alloc(size_t, xfs_km_flags_t); extern void *kmem_zalloc_large(size_t size, xfs_km_flags_t); extern void *kmem_realloc(const void *, size_t, xfs_km_flags_t); static inline void kmem_free(const void *ptr) { kvfree(ptr); } extern void *kmem_zalloc_greedy(size_t *, size_t, size_t); static inline void * kmem_zalloc(size_t size, xfs_km_flags_t flags) { return kmem_alloc(size, flags | KM_ZERO); } /* * Zone interfaces */ #define KM_ZONE_HWALIGN SLAB_HWCACHE_ALIGN #define KM_ZONE_RECLAIM SLAB_RECLAIM_ACCOUNT #define KM_ZONE_SPREAD SLAB_MEM_SPREAD #define KM_ZONE_ACCOUNT SLAB_ACCOUNT #define kmem_zone kmem_cache #define kmem_zone_t struct kmem_cache static inline kmem_zone_t * kmem_zone_init(int size, char *zone_name) { return kmem_cache_create(zone_name, size, 0, 0, NULL); } static inline kmem_zone_t * kmem_zone_init_flags(int size, char *zone_name, unsigned long flags, void (*construct)(void *)) { return kmem_cache_create(zone_name, size, 0, flags, construct); } static inline void kmem_zone_free(kmem_zone_t *zone, void *ptr) { kmem_cache_free(zone, ptr); } static inline void kmem_zone_destroy(kmem_zone_t *zone) { if (zone) kmem_cache_destroy(zone); } extern void *kmem_zone_alloc(kmem_zone_t *, xfs_km_flags_t); static inline void * kmem_zone_zalloc(kmem_zone_t *zone, xfs_km_flags_t flags) { return kmem_zone_alloc(zone, flags | KM_ZERO); } #endif /* __XFS_SUPPORT_KMEM_H__ */ mp;id=966d2b04e070bc040319aaebfec09e0144dc3341'>uapi/video/sisfb.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 /include/uapi/video/sisfb.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 'include/uapi/video/sisfb.h')