From mboxrd@z Thu Jan 1 00:00:00 1970 From: b32955@freescale.com (Huang Shijie) Date: Sun, 1 Apr 2012 15:09:24 +0800 Subject: Bug in v7_coherent_kern_range() ? In-Reply-To: <4F77F13D.7000402@googlemail.com> References: <4F77C9A6.6080601@freescale.com> <4F77F13D.7000402@googlemail.com> Message-ID: <4F77FF24.5010809@freescale.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Dirk: > Hi Huang Shijie, > > On 01.04.2012 05:21, Huang Shijie wrote: >> [1] Platform: >> freescale's IMX6Q(4 cores) , ARM CORTEX-A9 >> >> [2] kernel: >> 3.0.15(I have cherry-picked many patches, and the arch/arm/mm/cache-v7.S >> is same code with the latest kernel v3.4-rc1) >> enable SMP, VIPT, > > Could you try an unpatched, clean v3.4-rc1 instead? Sorry, I could not try the v3.4-rc1. Some our bsp drivers are not DT supported. > > What's about your 2.6.38? 2.6.38 is not a good version to run the imx6q. It losts many our drivers's patches. > > What's about 3.0.26? 3.0.15 seems to miss some maybe relevant patches. > Our bsp release are based on 3.0.15. so we could not test it on 3.0.26 too. >> [3] application: > > Could you share a (simple) test case? The test case is like this: #gplay xx.avi gplay is our own player, such as mplayer. I just created a script which will play the video files one by one. BR Huang Shijie > > Best regards > > Dirk > >> I use our our application which will clone many threads, >> two threads (assume as A and B) may do the same thing at the same time >> as the following code: >> >> In most of the time, it's ok. >> But in some unknown situation, cacheflush() failed and one threads >> (assume A) may hung up in the following code: >> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >> >> >> open("/usr/lib/lib_mp3_dec_arm12_elinux.so.2.10.0", O_RDONLY) = 8 >> read(8, >> "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\20\35\0\0004\0\0\0"..., >> 512) = 512 >> fstat64(8, {st_mode=S_IFREG|0644, st_size=56232, ...}) = 0 >> mmap2(NULL, 88032, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 8, 0) >> = 0x2ff0a000 >> mprotect(0x2ff18000, 28672, PROT_NONE) = 0 >> mmap2(0x2ff1f000, 4096, PROT_READ|PROT_WRITE, >> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 8, 0xd) = 0x2ff1f000 >> close(8) = 0 >> mprotect(0x2ff0a000, 57344, PROT_READ|PROT_WRITE) = 0 >> mprotect(0x2ff0a000, 57344, PROT_READ|PROT_EXEC) = 0 >> cacheflush(0x2ff0a000, 0x2ff18000, 0, 0x6, 0x2cd03420) = 0 // System >> hung up here!!! >> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >> >> >> >> [4] kernel log >> I use "echo t> /proc/sysrq-trigger" to show the tasks's information: >> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >> >> >> multiqueue0:src D 804cd678 0 7328 5963 0x00000001 >> [<804cd678>] (__schedule+0x228/0x760) from [<804d0564>] >> (__down_read+0xa8/0xe0) >> [<804d0564>] (__down_read+0xa8/0xe0) from [<800478c4>] >> (do_page_fault+0xbc/0x480) >> [<800478c4>] (do_page_fault+0xbc/0x480) from [<8003841c>] >> (do_DataAbort+0x34/0x98) >> [<8003841c>] (do_DataAbort+0x34/0x98) from [<8003df10>] >> (__dabt_svc+0x70/0xa0) >> Exception stack(0xbae37ea8 to 0xbae37ef0) >> 7ea0: 31e05000 31e1d000 00000020 0000001f 31e05000 31e1d000 >> 7ec0: bfac86b8 31e05000 31e1d000 bae36000 08100075 31e056fc 31e08000 >> bae37ef0 >> 7ee0: 800424a8 8004a1fc 800f0013 ffffffff >> [<8003df10>] (__dabt_svc+0x70/0xa0) from [<8004a1fc>] >> (v7_coherent_kern_range+0x20/0x80) >> [<8004a1fc>] (v7_coherent_kern_range+0x20/0x80) from [<800424a8>] >> (arm_syscall+0x2a0/0x2c4) >> [<800424a8>] (arm_syscall+0x2a0/0x2c4) from [<8003e500>] >> (ret_fast_syscall+0x0/0x3c) >> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >> >> >> >> The do_cache_op() has already held the mm->mmap_sem, but >> v7_coherent_kern_range() >> cause one page fault during it flush the cache. deadlock! So it hung up >> in the do_page_fault(). >> >> [5] questions: >> Why the v7_coherent_kern_range() can caused the data abort? >> Is there something wrong about the v7_coherent_kern_range()? >> >> >> thanks >> Huang Shijie >> >> >> >> >> >> _______________________________________________ >> linux-arm-kernel mailing list >> linux-arm-kernel at lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >> > >