#ifndef __ASM_GENERIC_SHMBUF_H #define __ASM_GENERIC_SHMBUF_H #include /* * The shmid64_ds structure for x86 architecture. * Note extra padding because this structure is passed back and forth * between kernel and user space. * * shmid64_ds was originally meant to be architecture specific, but * everyone just ended up making identical copies without specific * optimizations, so we may just as well all use the same one. * * 64 bit architectures typically define a 64 bit __kernel_time_t, * so they do not need the first two padding words. * On big-endian systems, the padding is in the wrong place. * * * Pad space is left for: * - 64-bit time_t to solve y2038 problem * - 2 miscellaneous 32-bit values */ struct shmid64_ds { struct ipc64_perm shm_perm; /* operation perms */ size_t shm_segsz; /* size of segment (bytes) */ __kernel_time_t shm_atime; /* last attach time */ #if __BITS_PER_LONG != 64 unsigned long __unused1; #endif __kernel_time_t shm_dtime; /* last detach time */ #if __BITS_PER_LONG != 64 unsigned long __unused2; #endif __kernel_time_t shm_ctime; /* last change time */ #if __BITS_PER_LONG != 64 unsigned long __unused3; #endif __kernel_pid_t shm_cpid; /* pid of creator */ __kernel_pid_t shm_lpid; /* pid of last operator */ __kernel_ulong_t shm_nattch; /* no. of current attaches */ __kernel_ulong_t __unused4; __kernel_ulong_t __unused5; }; struct shminfo64 { __kernel_ulong_t shmmax; __kernel_ulong_t shmmin; __kernel_ulong_t shmmni; __kernel_ulong_t shmseg; __kernel_ulong_t shmall; __kernel_ulong_t __unused1; __kernel_ulong_t __unused2; __kernel_ulong_t __unused3; __kernel_ulong_t __unused4; }; #endif /* __ASM_GENERIC_SHMBUF_H */ -next.git/log/net/appletalk?h=nds-private-remove'>logtreecommitdiff
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authorIago Abal <mail@iagoabal.eu>2017-01-11 14:00:21 +0100
committerVinod Koul <vinod.koul@intel.com>2017-01-25 15:35:11 +0530
commit91539eb1fda2d530d3b268eef542c5414e54bf1a (patch)
tree960f5ca6342ad20837aff18aad6e8ecd7da32fd6 /net/appletalk
parent6610d0edf6dc7ee97e46ab3a538a565c79d26199 (diff)
dmaengine: pl330: fix double lock
The static bug finder EBA (http://www.iagoabal.eu/eba/) reported the following double-lock bug: Double lock: 1. spin_lock_irqsave(pch->lock, flags) at pl330_free_chan_resources:2236; 2. call to function `pl330_release_channel' immediately after; 3. call to function `dma_pl330_rqcb' in line 1753; 4. spin_lock_irqsave(pch->lock, flags) at dma_pl330_rqcb:1505. I have fixed it as suggested by Marek Szyprowski. First, I have replaced `pch->lock' with `pl330->lock' in functions `pl330_alloc_chan_resources' and `pl330_free_chan_resources'. This avoids the double-lock by acquiring a different lock than `dma_pl330_rqcb'. NOTE that, as a result, `pl330_free_chan_resources' executes `list_splice_tail_init' on `pch->work_list' under lock `pl330->lock', whereas in the rest of the code `pch->work_list' is protected by `pch->lock'. I don't know if this may cause race conditions. Similarly `pch->cyclic' is written by `pl330_alloc_chan_resources' under `pl330->lock' but read by `pl330_tx_submit' under `pch->lock'. Second, I have removed locking from `pl330_request_channel' and `pl330_release_channel' functions. Function `pl330_request_channel' is only called from `pl330_alloc_chan_resources', so the lock is already held. Function `pl330_release_channel' is called from `pl330_free_chan_resources', which already holds the lock, and from `pl330_del'. Function `pl330_del' is called in an error path of `pl330_probe' and at the end of `pl330_remove', but I assume that there cannot be concurrent accesses to the protected data at those points. Signed-off-by: Iago Abal <mail@iagoabal.eu> Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
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