On 22 June 2015 at 09:04, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote: > On 22/06/15 06:41, Peng Fan wrote: >> We should not call dma_free_coherent if host->adma_table is NULL, >> otherwise may trigger panic. >> >>>From DMA-API.txt: >> " >> void >> dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, >> dma_addr_t dma_handle) >> >> Free a region of consistent memory you previously allocated. dev, >> size and dma_handle must all be the same as those passed into >> dma_alloc_coherent(). cpu_addr must be the virtual address returned by >> the dma_alloc_coherent(). >> " >> So we should check cpu_addr, but not directly call dma_free_coherent. >> >> I met this when porting xen, log: " >> sdhci: Secure Digital Host Controller Interface driver >> sdhci: Copyright(c) Pierre Ossman >> sdhci-pltfm: SDHCI platform and OF driver helper >> Unable to handle kernel NULL pointer dereference at virtual address 00000000 >> pgd = 80004000 >> [00000000] *pgd=00000000 >> Internal error: Oops: 5 [#1] PREEMPT SMP ARM >> Modules linked in: >> CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.14.38-02383-g5ccf32b-dirty #22 >> task: 84074000 ti: 84078000 task.ti: 84078000 >> PC is at bitmap_clear+0xc0/0xdc >> LR is at bitmap_clear+0x54/0xdc >> pc : [<8029deb8>] lr : [<8029de4c>] psr: 20000193 >> sp : 84079d80 ip : 00000001 fp : 00000000 >> r10: 00077fff r9 : 00000404 r8 : 00000001 >> r7 : 00000001 r6 : 00000001 r5 : 00000000 r4 : ffffffff >> r3 : 00000001 r2 : 00000001 r1 : 20000193 r0 : 00000015 >> Flags: nzCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel >> Control: 10c53c7d Table: 8800406a DAC: 00000015 >> Process swapper/0 (pid: 1, stack limit = 0x84078238) >> Stack: (0x84079d80 to 0x8407a000) >> 9d80: 80000113 00000000 87efa000 81109918 00001000 800197f8 84128558 00080008 >> 9da0: 84079dec 000000d0 84bfeac0 84126c10 84126c10 ffffffff 00000404 ffffffff >> 9dc0: 00000000 00000402 00000000 00000000 84126c10 80310ba8 ffffffff 00000000 >> 9de0: 00000000 00000524 84078000 00000000 00000000 ffffffff ffffffff 84bfeac0 >> 9e00: 84bfe800 8000b407 07eb0000 8116e0f8 00000000 804ee81c ffffffff ffffffff >> 9e20: 00000000 84126c10 84c92010 84bfeac0 00000000 84126c10 84126c00 84bfeac0 >> 9e40: 84078030 804f08e4 804f03d8 84126c10 fffffdfb 8115401c 8115401c 00000000 >> 9e60: 0000010f 80362330 803622ec 84126c10 811c8098 00000000 8115401c 80360b1c >> 9e80: 84126c10 8115401c 84126c44 00000000 80de1888 80360d28 00000000 8115401c >> 9ea0: 80360c9c 8035f10c 8406965c 84123634 8115401c 84c8bf80 8112f3c8 803602bc >> 9ec0: 80d08314 8115401c 00000006 8115401c 00000006 8116e080 8116e080 8036130c >> 9ee0: 00000000 80e00f78 00000006 800088dc 8400f900 80c94fe0 840bd480 80735184 >> 9f00: 00000000 8116e080 0000150c 8012d430 00000000 811105b0 60000113 00000001 >> 9f20: 87ffc576 8075ca38 0000010f 8004b0f0 80d66884 00000006 87ffc583 00000006 >> 9f40: 811105a0 80e00f78 00000006 8116e080 8116e080 80da150c 0000010f 80df4154 >> 9f60: 80df4148 80da1c4c 00000006 00000006 80da150c 9355553c 84079f9c 80731338 >> 9f80: 00000000 00000000 80727254 00000000 00000000 00000000 00000000 00000000 >> 9fa0: 00000000 8072725c 00000000 8000ecf8 00000000 00000000 00000000 00000000 >> 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 >> 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 9355553c 9355553c >> [<8029deb8>] (bitmap_clear) from [<800197f8>] (__arm_dma_free.isra.18+0xe4/0x228) >> [<800197f8>] (__arm_dma_free.isra.18) from [<80310ba8>] (xen_swiotlb_free_coherent+0xfc/0x140) >> [<80310ba8>] (xen_swiotlb_free_coherent) from [<804ee81c>] (sdhci_add_host+0xb34/0xe64) >> [<804ee81c>] (sdhci_add_host) from [<804f08e4>] (sdhci_esdhc_imx_probe+0x50c/0x808) >> [<804f08e4>] (sdhci_esdhc_imx_probe) from [<80362330>] (platform_drv_probe+0x44/0xa4) >> [<80362330>] (platform_drv_probe) from [<80360b1c>] (driver_probe_device+0x120/0x25c) >> [<80360b1c>] (driver_probe_device) from [<80360d28>] (__driver_attach+0x8c/0x90) >> [<80360d28>] (__driver_attach) from [<8035f10c>] (bus_for_each_dev+0x60/0x94) >> [<8035f10c>] (bus_for_each_dev) from [<803602bc>] (bus_add_driver+0x148/0x1f0) >> [<803602bc>] (bus_add_driver) from [<8036130c>] (driver_register+0x78/0xf8) >> [<8036130c>] (driver_register) from [<800088dc>] (do_one_initcall+0xf8/0x144) >> [<800088dc>] (do_one_initcall) from [<80da1c4c>] (kernel_init_freeable+0x138/0x1d8) >> [<80da1c4c>] (kernel_init_freeable) from [<8072725c>] (kernel_init+0x8/0xf0) >> [<8072725c>] (kernel_init) from [<8000ecf8>] (ret_from_fork+0x14/0x3c) >> Code: 10866003 1206601f 10633006 11e02312 (e5953000) >> ---[ end trace f6f103bb73cc0503 ]--- >> note: swapper/0[1] exited with preempt_count 1 >> Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b" >> >> Because dma_alloc_coherent fail, it returns NULL, then >> "if (!host->adma_table || !host->align_buffer)" will return true, then >> dma_free_coherent trigger panic. >> >> After applying this patch, no panic and all work well, kernel log: >> " >> sdhci: Secure Digital Host Controller Interface driver >> sdhci: Copyright(c) Pierre Ossman >> sdhci-pltfm: SDHCI platform and OF driver helper >> mmc0: Unable to allocate ADMA buffers. Falling back to standard DMA. >> mmc0: no vqmmc regulator found >> mmc0: SDHCI controller on 30b40000.usdhc [30b40000.usdhc] using DMA >> " >> >> Signed-off-by: Peng Fan <van.freenix@xxxxxxxxx> > > Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx> > > Looks like the problem started in v3.16 with: > > commit d1e49f77d7c7b75fdc022e1d46c1549bbc91c5b7 > Author: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx> > Date: Fri Apr 25 12:58:34 2014 +0100 > > mmc: sdhci: convert ADMA descriptors to a coherent allocation > > Thanks, applied for fixes. I cleaned up the change log, I think it was a bit too verbose and I also added above fixes tag which was pointed out by Adrian. Sorry for the delay! Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
