On Thu, Dec 27, 2012 at 08:20:37PM +0100, Lubomir Rintel wrote: > This fatally confuses dma_async_memcpy_buf_to_pg which thinks it signals an > out > of memory condition and retries indefinitelly, causing a soft lockup. The > threshold does not seem to be enforced by hardware (couldn't find anything > like > that in a datasheet) and things seems to work fine without it. If there's a > performance penalty, it probably should be dealt with in dmaengine. > > The following crash (with too small skb structure being dma_memcpy()'d) is > reprodcibly triggered by an accept() quickly followed by a read(): > http://v3.sk/~lkundrak/so-beautiful/crasher.pl > > BUG: soft lockup - CPU#0 stuck for 23s! [perl:715] > Modules linked in: > Pid: 715, comm: perl > CPU: 0 Not tainted (3.6.7-2.fc18.armv5tel.kirkwood #1) > PC is at mv_xor_prep_dma_memcpy+0x14/0x168 > LR is at dma_async_memcpy_pg_to_pg+0x100/0x1dc > sp : df197ce0 ip : c023816c fp : 00000000 > r10: c09a6720 r9 : 0000012a r8 : 115d7000 > r7 : ddd4f57c r6 : ddd4f57c r5 : ddd4f4a8 r4 : 00000034 > r3 : 00000034 r2 : 115d7000 r1 : 116b912a r0 : ddd4f57c > Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user > Control: 0005397f Table: 1f218000 DAC: 00000015 > [<c000edac>] (unwind_backtrace+0x0/0x124) from [<c0074ce4>] > (watchdog_timer_fn+0xf0/0x144) > [<c0074ce4>] (watchdog_timer_fn+0xf0/0x144) from [<c003aa10>] > (__run_hrtimer+0xb0/0x1d4) > [<c003aa10>] (__run_hrtimer+0xb0/0x1d4) from [<c003b224>] > (hrtimer_interrupt+0x104/0x250) > [<c003b224>] (hrtimer_interrupt+0x104/0x250) from [<c0016024>] > (orion_timer_interrupt+0x24/0x34) > [<c0016024>] (orion_timer_interrupt+0x24/0x34) from [<c0075470>] > (handle_irq_event_percpu+0x38/0x23c) > [<c0075470>] (handle_irq_event_percpu+0x38/0x23c) from [<c00756a4>] > (handle_irq_event+0x30/0x40) > [<c00756a4>] (handle_irq_event+0x30/0x40) from [<c0077cd4>] > (handle_level_irq+0xcc/0xdc) > [<c0077cd4>] (handle_level_irq+0xcc/0xdc) from [<c0074e9c>] > (generic_handle_irq+0x28/0x38) > [<c0074e9c>] (generic_handle_irq+0x28/0x38) from [<c0009b64>] > (handle_IRQ+0x68/0x8c) > [<c0009b64>] (handle_IRQ+0x68/0x8c) from [<c0444794>] (__irq_svc+0x34/0x78) > [<c0444794>] (__irq_svc+0x34/0x78) from [<c0238180>] > (mv_xor_prep_dma_memcpy+0x14/0x168) > [<c0238180>] (mv_xor_prep_dma_memcpy+0x14/0x168) from [<c0236010>] > (dma_async_memcpy_pg_to_pg+0x100/0x1dc) > [<c0236010>] (dma_async_memcpy_pg_to_pg+0x100/0x1dc) from [<c0237594>] > (dma_memcpy_pg_to_iovec+0xf0/0x180) > [<c0237594>] (dma_memcpy_pg_to_iovec+0xf0/0x180) from [<c03832f8>] > (dma_skb_copy_datagram_iovec+0x100/0x1d4) > [<c03832f8>] (dma_skb_copy_datagram_iovec+0x100/0x1d4) from [<c03a9950>] > (tcp_recvmsg+0x630/0xac0) > [<c03a9950>] (tcp_recvmsg+0x630/0xac0) from [<c03c8dd8>] > (inet_recvmsg+0x48/0x5c) > [<c03c8dd8>] (inet_recvmsg+0x48/0x5c) from [<c035ba54>] > (sock_aio_read+0x100/0x120) > [<c035ba54>] (sock_aio_read+0x100/0x120) from [<c00e53e0>] > (do_sync_read+0x98/0xd4) > [<c00e53e0>] (do_sync_read+0x98/0xd4) from [<c00e5d54>] (vfs_read+0xb4/0x184) > [<c00e5d54>] (vfs_read+0xb4/0x184) from [<c00e5e60>] (sys_read+0x3c/0x70) > [<c00e5e60>] (sys_read+0x3c/0x70) from [<c0008c60>] > (ret_fast_syscall+0x0/0x2c) > Kernel panic - not syncing: softlockup: hung tasks > [<c000edac>] (unwind_backtrace+0x0/0x124) from [<c043e0ac>] (panic+0x80/0x1e0) > [<c043e0ac>] (panic+0x80/0x1e0) from [<c0074d08>] > (watchdog_timer_fn+0x114/0x144) > [<c0074d08>] (watchdog_timer_fn+0x114/0x144) from [<c003aa10>] > (__run_hrtimer+0xb0/0x1d4) > [<c003aa10>] (__run_hrtimer+0xb0/0x1d4) from [<c003b224>] > (hrtimer_interrupt+0x104/0x250) > [<c003b224>] (hrtimer_interrupt+0x104/0x250) from [<c0016024>] > (orion_timer_interrupt+0x24/0x34) > [<c0016024>] (orion_timer_interrupt+0x24/0x34) from [<c0075470>] > (handle_irq_event_percpu+0x38/0x23c) > [<c0075470>] (handle_irq_event_percpu+0x38/0x23c) from [<c00756a4>] > (handle_irq_event+0x30/0x40) > [<c00756a4>] (handle_irq_event+0x30/0x40) from [<c0077cd4>] > (handle_level_irq+0xcc/0xdc) > [<c0077cd4>] (handle_level_irq+0xcc/0xdc) from [<c0074e9c>] > (generic_handle_irq+0x28/0x38) > [<c0074e9c>] (generic_handle_irq+0x28/0x38) from [<c0009b64>] > (handle_IRQ+0x68/0x8c) > [<c0009b64>] (handle_IRQ+0x68/0x8c) from [<c0444794>] (__irq_svc+0x34/0x78) > [<c0444794>] (__irq_svc+0x34/0x78) from [<c0238180>] > (mv_xor_prep_dma_memcpy+0x14/0x168) > [<c0238180>] (mv_xor_prep_dma_memcpy+0x14/0x168) from [<c0236010>] > (dma_async_memcpy_pg_to_pg+0x100/0x1dc) > [<c0236010>] (dma_async_memcpy_pg_to_pg+0x100/0x1dc) from [<c0237594>] > (dma_memcpy_pg_to_iovec+0xf0/0x180) > [<c0237594>] (dma_memcpy_pg_to_iovec+0xf0/0x180) from [<c03832f8>] > (dma_skb_copy_datagram_iovec+0x100/0x1d4) > [<c03832f8>] (dma_skb_copy_datagram_iovec+0x100/0x1d4) from [<c03a9950>] > (tcp_recvmsg+0x630/0xac0) > [<c03a9950>] (tcp_recvmsg+0x630/0xac0) from [<c03c8dd8>] > (inet_recvmsg+0x48/0x5c) > [<c03c8dd8>] (inet_recvmsg+0x48/0x5c) from [<c035ba54>] > (sock_aio_read+0x100/0x120) > [<c035ba54>] (sock_aio_read+0x100/0x120) from [<c00e53e0>] > (do_sync_read+0x98/0xd4) > [<c00e53e0>] (do_sync_read+0x98/0xd4) from [<c00e5d54>] (vfs_read+0xb4/0x184) > [<c00e5d54>] (vfs_read+0xb4/0x184) from [<c00e5e60>] (sys_read+0x3c/0x70) > [<c00e5e60>] (sys_read+0x3c/0x70) from [<c0008c60>] > (ret_fast_syscall+0x0/0x2c) > Rebooting in 1 seconds.. > > Signed-off-by: Lubomir Rintel <[email protected]> > --- > drivers/dma/mv_xor.c | 7 ------- > drivers/dma/mv_xor.h | 1 - > 2 files changed, 0 insertions(+), 8 deletions(-)
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