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From: Roman Gushchin To: netdev@vger.kernel.org, Jakub Kicinski , "David S. Miller" Cc: linux-kernel@vger.kernel.org, Rafal Ozieblo , Lars-Peter Clausen Subject: Re: [PATCH net] net: macb: fix a memory corruption in extended buffer descriptor mode Message-ID: References: <20230407172402.103168-1-roman.gushchin@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230407172402.103168-1-roman.gushchin@linux.dev> X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Friendly ping. Also cc'ing Dave. Thanks! On Fri, Apr 07, 2023 at 10:24:02AM -0700, Roman Gushchin wrote: > For quite some time we were chasing a bug which looked like a sudden > permanent failure of networking and mmc on some of our devices. > The bug was very sensitive to any software changes and even more to > any kernel debug options. > > Finally we got a setup where the problem was reproducible with > CONFIG_DMA_API_DEBUG=y and it revealed the issue with the rx dma: > > [ 16.992082] ------------[ cut here ]------------ > [ 16.996779] DMA-API: macb ff0b0000.ethernet: device driver tries to free DMA memory it has not allocated [device address=0x0000000875e3e244] [size=1536 bytes] > [ 17.011049] WARNING: CPU: 0 PID: 85 at kernel/dma/debug.c:1011 check_unmap+0x6a0/0x900 > [ 17.018977] Modules linked in: xxxxx > [ 17.038823] CPU: 0 PID: 85 Comm: irq/55-8000f000 Not tainted 5.4.0 #28 > [ 17.045345] Hardware name: xxxxx > [ 17.049528] pstate: 60000005 (nZCv daif -PAN -UAO) > [ 17.054322] pc : check_unmap+0x6a0/0x900 > [ 17.058243] lr : check_unmap+0x6a0/0x900 > [ 17.062163] sp : ffffffc010003c40 > [ 17.065470] x29: ffffffc010003c40 x28: 000000004000c03c > [ 17.070783] x27: ffffffc010da7048 x26: ffffff8878e38800 > [ 17.076095] x25: ffffff8879d22810 x24: ffffffc010003cc8 > [ 17.081407] x23: 0000000000000000 x22: ffffffc010a08750 > [ 17.086719] x21: ffffff8878e3c7c0 x20: ffffffc010acb000 > [ 17.092032] x19: 0000000875e3e244 x18: 0000000000000010 > [ 17.097343] x17: 0000000000000000 x16: 0000000000000000 > [ 17.102647] x15: ffffff8879e4a988 x14: 0720072007200720 > [ 17.107959] x13: 0720072007200720 x12: 0720072007200720 > [ 17.113261] x11: 0720072007200720 x10: 0720072007200720 > [ 17.118565] x9 : 0720072007200720 x8 : 000000000000022d > [ 17.123869] x7 : 0000000000000015 x6 : 0000000000000098 > [ 17.129173] x5 : 0000000000000000 x4 : 0000000000000000 > [ 17.134475] x3 : 00000000ffffffff x2 : ffffffc010a1d370 > [ 17.139778] x1 : b420c9d75d27bb00 x0 : 0000000000000000 > [ 17.145082] Call trace: > [ 17.147524] check_unmap+0x6a0/0x900 > [ 17.151091] debug_dma_unmap_page+0x88/0x90 > [ 17.155266] gem_rx+0x114/0x2f0 > [ 17.158396] macb_poll+0x58/0x100 > [ 17.161705] net_rx_action+0x118/0x400 > [ 17.165445] __do_softirq+0x138/0x36c > [ 17.169100] irq_exit+0x98/0xc0 > [ 17.172234] __handle_domain_irq+0x64/0xc0 > [ 17.176320] gic_handle_irq+0x5c/0xc0 > [ 17.179974] el1_irq+0xb8/0x140 > [ 17.183109] xiic_process+0x5c/0xe30 > [ 17.186677] irq_thread_fn+0x28/0x90 > [ 17.190244] irq_thread+0x208/0x2a0 > [ 17.193724] kthread+0x130/0x140 > [ 17.196945] ret_from_fork+0x10/0x20 > [ 17.200510] ---[ end trace 7240980785f81d6f ]--- > > [ 237.021490] ------------[ cut here ]------------ > [ 237.026129] DMA-API: exceeded 7 overlapping mappings of cacheline 0x0000000021d79e7b > [ 237.033886] WARNING: CPU: 0 PID: 0 at kernel/dma/debug.c:499 add_dma_entry+0x214/0x240 > [ 237.041802] Modules linked in: xxxxx > [ 237.061637] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 5.4.0 #28 > [ 237.068941] Hardware name: xxxxx > [ 237.073116] pstate: 80000085 (Nzcv daIf -PAN -UAO) > [ 237.077900] pc : add_dma_entry+0x214/0x240 > [ 237.081986] lr : add_dma_entry+0x214/0x240 > [ 237.086072] sp : ffffffc010003c30 > [ 237.089379] x29: ffffffc010003c30 x28: ffffff8878a0be00 > [ 237.094683] x27: 0000000000000180 x26: ffffff8878e387c0 > [ 237.099987] x25: 0000000000000002 x24: 0000000000000000 > [ 237.105290] x23: 000000000000003b x22: ffffffc010a0fa00 > [ 237.110594] x21: 0000000021d79e7b x20: ffffffc010abe600 > [ 237.115897] x19: 00000000ffffffef x18: 0000000000000010 > [ 237.121201] x17: 0000000000000000 x16: 0000000000000000 > [ 237.126504] x15: ffffffc010a0fdc8 x14: 0720072007200720 > [ 237.131807] x13: 0720072007200720 x12: 0720072007200720 > [ 237.137111] x11: 0720072007200720 x10: 0720072007200720 > [ 237.142415] x9 : 0720072007200720 x8 : 0000000000000259 > [ 237.147718] x7 : 0000000000000001 x6 : 0000000000000000 > [ 237.153022] x5 : ffffffc010003a20 x4 : 0000000000000001 > [ 237.158325] x3 : 0000000000000006 x2 : 0000000000000007 > [ 237.163628] x1 : 8ac721b3a7dc1c00 x0 : 0000000000000000 > [ 237.168932] Call trace: > [ 237.171373] add_dma_entry+0x214/0x240 > [ 237.175115] debug_dma_map_page+0xf8/0x120 > [ 237.179203] gem_rx_refill+0x190/0x280 > [ 237.182942] gem_rx+0x224/0x2f0 > [ 237.186075] macb_poll+0x58/0x100 > [ 237.189384] net_rx_action+0x118/0x400 > [ 237.193125] __do_softirq+0x138/0x36c > [ 237.196780] irq_exit+0x98/0xc0 > [ 237.199914] __handle_domain_irq+0x64/0xc0 > [ 237.204000] gic_handle_irq+0x5c/0xc0 > [ 237.207654] el1_irq+0xb8/0x140 > [ 237.210789] arch_cpu_idle+0x40/0x200 > [ 237.214444] default_idle_call+0x18/0x30 > [ 237.218359] do_idle+0x200/0x280 > [ 237.221578] cpu_startup_entry+0x20/0x30 > [ 237.225493] rest_init+0xe4/0xf0 > [ 237.228713] arch_call_rest_init+0xc/0x14 > [ 237.232714] start_kernel+0x47c/0x4a8 > [ 237.236367] ---[ end trace 7240980785f81d70 ]--- > > Lars was fast to find an explanation: according to the datasheet > bit 2 of the rx buffer descriptor entry has a different meaning in the > extended mode: > Address [2] of beginning of buffer, or > in extended buffer descriptor mode (DMA configuration register [28] = 1), > indicates a valid timestamp in the buffer descriptor entry. > > The macb driver didn't mask this bit while getting an address and it > eventually caused a memory corruption and a dma failure. > > The problem is resolved by extending the MACB_RX_WADDR_SIZE > in the extended mode. > > Fixes: 7b4296148066 ("net: macb: Add support for PTP timestamps in DMA descriptors") > Signed-off-by: Roman Gushchin > Co-developed-by: Lars-Peter Clausen > Signed-off-by: Lars-Peter Clausen > --- > drivers/net/ethernet/cadence/macb.h | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h > index c1fc91c97cee..1b330f7cfc09 100644 > --- a/drivers/net/ethernet/cadence/macb.h > +++ b/drivers/net/ethernet/cadence/macb.h > @@ -826,8 +826,13 @@ struct macb_dma_desc_ptp { > #define MACB_RX_USED_SIZE 1 > #define MACB_RX_WRAP_OFFSET 1 > #define MACB_RX_WRAP_SIZE 1 > +#ifdef MACB_EXT_DESC > +#define MACB_RX_WADDR_OFFSET 3 > +#define MACB_RX_WADDR_SIZE 29 > +#else > #define MACB_RX_WADDR_OFFSET 2 > #define MACB_RX_WADDR_SIZE 30 > +#endif > > #define MACB_RX_FRMLEN_OFFSET 0 > #define MACB_RX_FRMLEN_SIZE 12 > -- > 2.40.0 >