Hi I am getting a kernel oops[1] during boot on imx28 with emmc flash right around rootfs mounting. Using git bisect I found the cause to be the following commit. Regression: ceeeb99cd821 ("dmaengine: mxs: rename custom flag") Reverting the 2 changes in drivers/dma/mxs-dma.c fixes the oops, but I am not sure that is the right solution as I don't have the full mxs-dma + mtd/mmc overview. I did see that the patch isn't a simple rename but also a bit define change. From: DMA_CTRL_ACK = (1 << 1) = BIT(1) To: MXS_DMA_CTRL_WAIT4END = BIT(31) Bruno [1] One of the kernel oops during git bisect (dirty part is just a dts). [ 2.326402] 8<--- cut here --- [ 2.329575] Unable to handle kernel NULL pointer dereference at virtual address 00000252 [ 2.337988] pgd = (ptrval) [ 2.340793] [00000252] *pgd=00000000 [ 2.344483] Internal error: Oops: 5 [#1] ARM [ 2.348790] Modules linked in: [ 2.351904] CPU: 0 PID: 21 Comm: kworker/0:1 Not tainted 5.2.0-10687-g5fe7b600a116-dirty #6 [ 2.360283] Hardware name: Freescale MXS (Device Tree) [ 2.365480] Workqueue: events_freezable mmc_rescan [ 2.370324] PC is at mmc_wait_for_cmd+0x30/0xa4 [ 2.374893] LR is at mmc_wait_for_cmd+0x30/0xa4 [ 2.379453] pc : [<c0389608>] lr : [<c0389608>] psr: 40000013 [ 2.385748] sp : cf5d9d20 ip : cf5d9d9c fp : cf73ca64 [ 2.391000] r10: 00000001 r9 : cf68f2b0 r8 : 00200000 [ 2.396254] r7 : 00000000 r6 : ffffff92 r5 : c0701068 r4 : cf5d9db8 [ 2.402810] r3 : 00000000 r2 : fffffffc r1 : 00000000 r0 : cf5d9d20 [ 2.409368] Flags: nZcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none [ 2.416537] Control: 0005317f Table: 40004000 DAC: 00000053 [ 2.422315] Process kworker/0:1 (pid: 21, stack limit = 0x(ptrval)) [ 2.428611] Stack: (0xcf5d9d20 to 0xcf5da000) [ 2.433016] 9d20: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 2.441237] 9d40: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 2.449460] 9d60: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 2.457680] 9d80: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 3a80845c [ 2.465903] 9da0: 0000000a c0701068 ffffff92 00200000 0000000a c0392b0c 00000008 000001aa [ 2.474125] 9dc0: 00000000 00000000 00000000 00000000 000002f5 00000000 00000000 00000000 [ 2.482347] 9de0: 00000000 00000000 00000000 3a80845c ffffff92 00200000 00000000 c0391a28 [ 2.490569] 9e00: 00000000 cf68f000 cf73c800 cf73ca64 00200000 00200000 0000000a 00000000 [ 2.498795] 9e20: c0701068 c03937b0 cf5d9e3c 3a80845c cf5d9e54 c030466c c0634ef0 c06484f0 [ 2.507021] 9e40: cf4f4680 cf5d9e54 c0701068 c03048c0 ffffff92 ffffff3f cf5d9e50 3a80845c [ 2.515244] 9e60: c0760fc0 cf68f338 00000001 cf68f000 cf68f000 c0760fc0 c0525400 c0701068 [ 2.523466] 9e80: 00000000 c0394460 00000008 000001aa ffffff3f 00000000 00000000 00000000 [ 2.531689] 9ea0: ffffff3f 3a80845c 00000000 cf68f338 00000001 cf68f000 ffffff92 c0760fc0 [ 2.539915] 9ec0: c0525400 c0525410 c0760fb0 c038b47c 00000000 c0708ca4 cf68f338 cf68f338 [ 2.548139] 9ee0: cf5aa540 c0708ca4 cfde0600 cf5d9f1c c075a9f9 c075b414 c0701068 c0035298 [ 2.556363] 9f00: 00000001 00000000 c0035200 c04eb0c8 00000000 00000000 c00356e8 c0dceb08 [ 2.564588] 9f20: c0bbe570 00000000 c06467a0 3a80845c c0708ca4 cf5aa540 c0708ca4 cf5aa554 [ 2.572811] 9f40: c0708cd8 ffffe000 c070ff60 00000008 c0708ca4 c0035644 60000053 cf5cb244 [ 2.581035] 9f60: ffffe000 cf5b7280 cf5a3fc0 00000000 cf5d8000 cf5aa540 c0035618 cf49be90 [ 2.589260] 9f80: cf5b72b8 c003aae8 20000053 cf5a3fc0 c003a9c8 00000000 00000000 00000000 [ 2.597483] 9fa0: 00000000 00000000 00000000 c00090b0 00000000 00000000 00000000 00000000 [ 2.605703] 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 2.613924] 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000 [ 2.622176] [<c0389608>] (mmc_wait_for_cmd) from [<c0392b0c>] (mmc_send_if_cond+0x64/0xb0) [ 2.630507] [<c0392b0c>] (mmc_send_if_cond) from [<c0391a28>] (mmc_sd_get_cid+0x40/0x164) [ 2.638750] [<c0391a28>] (mmc_sd_get_cid) from [<c03937b0>] (mmc_sdio_init_card+0x28c/0xcb0) [ 2.647249] [<c03937b0>] (mmc_sdio_init_card) from [<c0394460>] (mmc_attach_sdio+0x90/0x350) [ 2.655744] [<c0394460>] (mmc_attach_sdio) from [<c038b47c>] (mmc_rescan+0x370/0x448) [ 2.663646] [<c038b47c>] (mmc_rescan) from [<c0035298>] (process_one_work+0x220/0x5a0) [ 2.671629] [<c0035298>] (process_one_work) from [<c0035644>] (worker_thread+0x2c/0x50c) [ 2.679783] [<c0035644>] (worker_thread) from [<c003aae8>] (kthread+0x120/0x134) [ 2.687232] [<c003aae8>] (kthread) from [<c00090b0>] (ret_from_fork+0x14/0x24) [ 2.694488] Exception stack(0xcf5d9fb0 to 0xcf5d9ff8) [ 2.699581] 9fa0: 00000000 00000000 00000000 00000000 [ 2.707803] 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 2.716018] 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 [ 2.722683] Code: e3a0207c e3a01000 e58d307c eb050cad (e5d632c0) [ 2.729008] ---[ end trace bc2ac96ca83a59e7 ]---