2015-06-30 9:56 GMT+09:00 Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>: > On 29.06.2015 22:22, Robert Baldyga wrote: >> Enable DMA transfers for serial ports. >> >> Signed-off-by: Robert Baldyga <r.baldyga@xxxxxxxxxxx> >> --- >> arch/arm/boot/dts/exynos4.dtsi | 8 ++++++++ >> 1 file changed, 8 insertions(+) > > Reviewed-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx> Unfortunately the commit (applied on 4.2-rc1) exposes lock-ups during Trats2 boot. Board: Trats2 Config: exynos Tree: https://github.com/krzk/linux.git branch: for-next (v4.2-rc1-29-g1ce41c343055) Lockdep indicated issue in Samsung serial driver (dma_async_issue_pending called while holding port->lock which leads to calling back the driver's tx_dma_complete). I tried to locate the dead lock. To me the excessive locking in serial driver causes such recursive locking but I am not quite sure (I am not familiar with the serial driver). Anyway, till this get fixed I am dropping the patch from my tree. Best regards, Krzysztof Bug (I hope line wrapping won't mess up with it...): [ 74.480535] BUG: spinlock recursion on CPU#1, systemd/1 [ 74.484293] lock: 0xeeb1a9f4, .magic: dead4ead, .owner: systemd/1, .owner_cpu: 1 [ 74.491756] CPU: 1 PID: 1 Comm: systemd Not tainted 4.2.0-rc1-00029-g1ce41c343055 #100 [ 74.499649] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [ 74.505752] [<c0014d2c>] (unwind_backtrace) from [<c0011c98>] (show_stack+0x10/0x14) [ 74.513461] [<c0011c98>] (show_stack) from [<c051f198>] (dump_stack+0x70/0xbc) [ 74.520668] [<c051f198>] (dump_stack) from [<c00562b0>] (do_raw_spin_lock+0x178/0x1a0) [ 74.528568] [<c00562b0>] (do_raw_spin_lock) from [<c0524e90>] (_raw_spin_lock_irqsave+0x20/0x28) [ 74.537330] [<c0524e90>] (_raw_spin_lock_irqsave) from [<c024288c>] (dma_pl330_rqcb.isra.4+0x24/0x58) [ 74.546529] [<c024288c>] (dma_pl330_rqcb.isra.4) from [<c0242d78>] (pl330_release_channel.part.5+0x38/0x98) [ 74.556249] [<c0242d78>] (pl330_release_channel.part.5) from [<c0242e2c>] (pl330_free_chan_resources+0x54/0xd8) [ 74.566324] [<c0242e2c>] (pl330_free_chan_resources) from [<c0240144>] (dma_chan_put+0x88/0x8c) [ 74.575001] [<c0240144>] (dma_chan_put) from [<c024016c>] (dma_release_channel+0x24/0x94) [ 74.583163] [<c024016c>] (dma_release_channel) from [<c0271498>] (s3c24xx_serial_shutdown+0x18c/0x1d8) [ 74.592447] [<c0271498>] (s3c24xx_serial_shutdown) from [<c026ab28>] (uart_port_shutdown+0x2c/0x38) [ 74.601472] [<c026ab28>] (uart_port_shutdown) from [<c026acc4>] (uart_shutdown+0xac/0xec) [ 74.609630] [<c026acc4>] (uart_shutdown) from [<c026ae3c>] (uart_close+0x64/0x1f0) [ 74.617184] [<c026ae3c>] (uart_close) from [<c0251544>] (tty_release+0xf0/0x464) [ 74.624566] [<c0251544>] (tty_release) from [<c00cca38>] (__fput+0x80/0x1bc) [ 74.631594] [<c00cca38>] (__fput) from [<c00384d0>] (task_work_run+0xa8/0xdc) [ 74.638711] [<c00384d0>] (task_work_run) from [<c00118dc>] (do_work_pending+0x94/0xb4) [ 74.646610] [<c00118dc>] (do_work_pending) from [<c000f54c>] (work_pending+0xc/0x20) Lockdep: [ 109.696678] #### Requested RX ee0d4a2c@TX ee0d4ac4 [ 109.701699] [ 109.701928] ============================================= [ 109.707310] [ INFO: possible recursive locking detected ] [ 109.712694] 4.2.0-rc1-00029-g1ce41c343055-dirty #111 Not tainted [ 109.718680] --------------------------------------------- [ 109.724063] swapper/0/0 is trying to acquire lock: [ 109.728836] (&port_lock_key){-.-...}, at: [<c02ad78c>] s3c24xx_serial_tx_dma_complete+0x8c/0xfc [ 109.737603] [ 109.737603] but task is already holding lock: [ 109.743418] (&port_lock_key){-.-...}, at: [<c02ac014>] s3c24xx_serial_tx_chars+0x18/0x180 [ 109.751664] [ 109.751664] other info that might help us debug this: [ 109.758174] Possible unsafe locking scenario: [ 109.758174] [ 109.764076] CPU0 [ 109.766507] ---- [ 109.768936] lock(&port_lock_key); [ 109.772408] lock(&port_lock_key); [ 109.775881] [ 109.775881] *** DEADLOCK *** [ 109.775881] [ 109.781784] May be due to missing lock nesting notation [ 109.781784] [ 109.788556] 1 lock held by swapper/0/0: [ 109.792373] #0: (&port_lock_key){-.-...}, at: [<c02ac014>] s3c24xx_serial_tx_chars+0x18/0x180 [ 109.801053] [ 109.801053] stack backtrace: [ 109.805399] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.2.0-rc1-00029-g1ce41c343055-dirty #111 [ 109.813988] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [ 109.820084] [<c0015e9c>] (unwind_backtrace) from [<c0012c18>] (show_stack+0x10/0x14) [ 109.827801] [<c0012c18>] (show_stack) from [<c0599b7c>] (dump_stack+0x70/0xbc) [ 109.835003] [<c0599b7c>] (dump_stack) from [<c00649ec>] (validate_chain.isra.24+0x7b4/0x8b8) [ 109.843419] [<c00649ec>] (validate_chain.isra.24) from [<c00656c4>] (__lock_acquire+0x464/0xb28) [ 109.852185] [<c00656c4>] (__lock_acquire) from [<c0066100>] (lock_acquire+0x6c/0x8c) [ 109.859915] [<c0066100>] (lock_acquire) from [<c05a0e68>] (_raw_spin_lock_irqsave+0x48/0x5c) [ 109.868335] [<c05a0e68>] (_raw_spin_lock_irqsave) from [<c02ad78c>] (s3c24xx_serial_tx_dma_complete+0x8c/0xfc) [ 109.878322] [<c02ad78c>] (s3c24xx_serial_tx_dma_complete) from [<c027b57c>] (pl330_tasklet+0x16c/0x4cc) [ 109.887690] [<c027b57c>] (pl330_tasklet) from [<c02abf4c>] (s3c24xx_serial_start_tx_dma+0x1a4/0x1f4) [ 109.896803] [<c02abf4c>] (s3c24xx_serial_start_tx_dma) from [<c02ac154>] (s3c24xx_serial_tx_chars+0x158/0x180) [ 109.906784] [<c02ac154>] (s3c24xx_serial_tx_chars) from [<c02ad5ec>] (s3c64xx_serial_handle_irq+0x34/0x60) [ 109.916424] [<c02ad5ec>] (s3c64xx_serial_handle_irq) from [<c0070f7c>] (handle_irq_event_percpu+0x50/0x154) [ 109.926142] [<c0070f7c>] (handle_irq_event_percpu) from [<c00710c0>] (handle_irq_event+0x40/0x64) [ 109.934995] [<c00710c0>] (handle_irq_event) from [<c0073fec>] (handle_fasteoi_irq+0xdc/0x1a4) [ 109.943501] [<c0073fec>] (handle_fasteoi_irq) from [<c0070850>] (generic_handle_irq+0x20/0x30) [ 109.952095] [<c0070850>] (generic_handle_irq) from [<c007096c>] (__handle_domain_irq+0x6c/0xe4) [ 109.960774] [<c007096c>] (__handle_domain_irq) from [<c0009474>] (gic_handle_irq+0x2c/0x68) [ 109.969105] [<c0009474>] (gic_handle_irq) from [<c0013744>] (__irq_svc+0x44/0x7c) [ 109.976566] Exception stack(0xc085df28 to 0xc085df70) [ 109.981603] df20: 00000001 00000001 00000000 c0860e78 8a83f452 00000019 [ 109.989763] df40: 8a95ae3e 00000019 eef70490 c088b8c4 00000000 c088b8c4 00000000 c085df70 [ 109.997919] df60: c0066a34 c04154b4 200b0013 ffffffff [ 110.002965] [<c0013744>] (__irq_svc) from [<c04154b4>] (cpuidle_enter_state+0x1f8/0x28c) [ 110.011037] [<c04154b4>] (cpuidle_enter_state) from [<c005d464>] (cpu_startup_entry+0x158/0x26c) [ 110.019804] [<c005d464>] (cpu_startup_entry) from [<c07f8c48>] (start_kernel+0x370/0x3dc) [ 120.694973] BUG: spinlock lockup suspected on CPU#0, swapper/0/0 [ 120.699509] lock: s3c24xx_serial_ports+0x2dc/0x560, .magic: dead4ead, .owner: swapper/0/0, .owner_cpu: 0 [ 120.709050] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.2.0-rc1-00029-g1ce41c343055-dirty #111 [ 120.717638] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [ 120.723727] [<c0015e9c>] (unwind_backtrace) from [<c0012c18>] (show_stack+0x10/0x14) [ 120.731450] [<c0012c18>] (show_stack) from [<c0599b7c>] (dump_stack+0x70/0xbc) [ 120.738652] [<c0599b7c>] (dump_stack) from [<c0069ca4>] (do_raw_spin_lock+0x114/0x1a0) [ 120.746552] [<c0069ca4>] (do_raw_spin_lock) from [<c05a0e70>] (_raw_spin_lock_irqsave+0x50/0x5c) [ 120.755321] [<c05a0e70>] (_raw_spin_lock_irqsave) from [<c02ad78c>] (s3c24xx_serial_tx_dma_complete+0x8c/0xfc) [ 120.765304] [<c02ad78c>] (s3c24xx_serial_tx_dma_complete) from [<c027b57c>] (pl330_tasklet+0x16c/0x4cc) [ 120.774675] [<c027b57c>] (pl330_tasklet) from [<c02abf4c>] (s3c24xx_serial_start_tx_dma+0x1a4/0x1f4) [ 120.783788] [<c02abf4c>] (s3c24xx_serial_start_tx_dma) from [<c02ac154>] (s3c24xx_serial_tx_chars+0x158/0x180) [ 120.793770] [<c02ac154>] (s3c24xx_serial_tx_chars) from [<c02ad5ec>] (s3c64xx_serial_handle_irq+0x34/0x60) [ 120.803408] [<c02ad5ec>] (s3c64xx_serial_handle_irq) from [<c0070f7c>] (handle_irq_event_percpu+0x50/0x154) [ 120.813128] [<c0070f7c>] (handle_irq_event_percpu) from [<c00710c0>] (handle_irq_event+0x40/0x64) [ 120.821980] [<c00710c0>] (handle_irq_event) from [<c0073fec>] (handle_fasteoi_irq+0xdc/0x1a4) [ 120.830486] [<c0073fec>] (handle_fasteoi_irq) from [<c0070850>] (generic_handle_irq+0x20/0x30) [ 120.839080] [<c0070850>] (generic_handle_irq) from [<c007096c>] (__handle_domain_irq+0x6c/0xe4) [ 120.847759] [<c007096c>] (__handle_domain_irq) from [<c0009474>] (gic_handle_irq+0x2c/0x68) [ 120.856090] [<c0009474>] (gic_handle_irq) from [<c0013744>] (__irq_svc+0x44/0x7c) [ 120.863550] Exception stack(0xc085df28 to 0xc085df70) [ 120.868588] df20: 00000001 00000001 00000000 c0860e78 8a83f452 00000019 [ 120.876748] df40: 8a95ae3e 00000019 eef70490 c088b8c4 00000000 c088b8c4 00000000 c085df70 [ 120.884904] df60: c0066a34 c04154b4 200b0013 ffffffff [ 120.889946] [<c0013744>] (__irq_svc) from [<c04154b4>] (cpuidle_enter_state+0x1f8/0x28c) [ 120.898019] [<c04154b4>] (cpuidle_enter_state) from [<c005d464>] (cpu_startup_entry+0x158/0x26c) [ 120.906785] [<c005d464>] (cpu_startup_entry) from [<c07f8c48>] (start_kernel+0x370/0x3dc) -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
