On Thu, Dec 15, 2011 at 12:04:42PM +0100, Claudio Scordino wrote: > Il 15/12/2011 11:00, Nicolas Ferre ha scritto: > >On 12/15/2011 09:47 AM, Claudio Scordino : > >>Hi all. > >> > >>We have encountered a spinlock lockup in the RS485 part of the > >>atmel_serial driver. > >> > >>Here is the trace: > >> > >>[ 68.030000] BUG: spinlock lockup on CPU#0, dnp_master/244, c07e82c0 > >>[ 68.040000] [<c002a790>] (unwind_backtrace+0x0/0xf0) from > >>[<c012f8f0>] (do_raw_spin_lock+0x10c/0x148) > >>[ 68.050000] [<c012f8f0>] (do_raw_spin_lock+0x10c/0x148) from > >>[<c015152c>] (atmel_tasklet_func+0x10/0x708) > >>[ 68.060000] [<c015152c>] (atmel_tasklet_func+0x10/0x708) from > >>[<c003bfd4>] (tasklet_action+0x8c/0xf4) > >>[ 68.070000] [<c003bfd4>] (tasklet_action+0x8c/0xf4) from [<c003c630>] > >>(__do_softirq+0xa4/0x180) > >>[ 68.080000] [<c003c630>] (__do_softirq+0xa4/0x180) from [<c003c764>] > >>(irq_exit+0x58/0xb0) > >>[ 68.090000] [<c003c764>] (irq_exit+0x58/0xb0) from [<c0021084>] > >>(asm_do_IRQ+0x84/0xa4) > >>[ 68.100000] [<c0021084>] (asm_do_IRQ+0x84/0xa4) from [<c002622c>] > >>(__irq_svc+0x4c/0x98) > >>[ 68.110000] Exception stack(0xc341fdc8 to 0xc341fe10) > >>[ 68.110000] fdc0: c07e82c0 00000000 00000200 > >>c4818000 c341fe10 c07e82c0 > >>[ 68.120000] fde0: 00000000 c07e82c0 c38d3318 c341e000 bebcee00 > >>010a0b60 c07e83fc c341fe10 > >>[ 68.130000] fe00: c0151d54 c023d9c0 60000013 ffffffff > >>[ 68.140000] [<c002622c>] (__irq_svc+0x4c/0x98) from [<c023d9c0>] > >>(_raw_spin_unlock+0x0/0x48) > >>[ 68.140000] [<c023d9c0>] (_raw_spin_unlock+0x0/0x48) from > >>[<00000000>] ( (null)) > >> > >>The soft lockup occurs later > >> > >>[ 126.750000] BUG: soft lockup - CPU#0 stuck for 61s! [dnp_master:244] > >>[ 126.750000] irq event stamp: 0 > >>[ 126.750000] hardirqs last enabled at (0): [< (null)>] (null) > >>[ 126.750000] hardirqs last disabled at (0): [<c0035e30>] > >>copy_process+0x308/0xe78 > >>[ 126.750000] softirqs last enabled at (0): [<c0035e30>] > >>copy_process+0x308/0xe78 > >>[ 126.750000] softirqs last disabled at (0): [< (null)>] (null) > >> > >> > >>The following patch (already tested by Dave, who also reported the bug) > >>fixes the problem. > >> > >>Regards, > >> > >> Claudio > >> > >> > >> > >> > >>Subject: atmel_serial: fix spinlock lockup in RS485 code > >> > >>Patch to fix a spinlock lockup in the driver that sometimes happens when > >>the > >>tasklet starts. > >> > >>Signed-off-by: Claudio Scordino<claudio@xxxxxxxxxxxxxxx> > >>Signed-off-by: Dave Bender<codehero@xxxxxxxxx> > >>Tested-by: Dave Bender<codehero@xxxxxxxxx> > > > >Acked-by: Nicolas Ferre<nicolas.ferre@xxxxxxxxx> > > > >Claudio, can you please send the patch to Alan with my "Acked-by" and an > >addition to Linux stable just after the signature lines: > > > >Cc: stable<stable@xxxxxxxxxx> That address has been invalid since August, please use stable@xxxxxxxxxxxxxxx now. > Dear Alan, > > here is the patch with all the acked-bys. I'll take care of this. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
