pigpio: 1-wire doesn't work when using pigpiod

I’m having issues with pigpiod in combination with 1-wire. When pigpiod is not running, the 1-wire sensor (DS18B20) can be read without any problems.

However, when I’m also reading measurements from a DHT22 – using pigpiod and the DHTXXD executable – I find that the 1-wire sensor file (w1_slave) occasionally disappears from /sys/bus/w1/devices/28*/. (DS18B20 id: 28-000006978d28)

Ultimately, this ends in a kernel “Oops” like this (sorry journalctl lines seem to have been truncated):

Apr 26 18:49:24 rbagain kernel: Unable to handle kernel NULL pointer dereference at virtual address 00000004
Apr 26 18:49:24 rbagain kernel: pgd = dd3e0000
Apr 26 18:49:24 rbagain kernel: [00000004] *pgd=1d2da831, *pte=00000000, *ppte=00000000
Apr 26 18:49:25 rbagain kernel: Internal error: Oops: 817 [#1] PREEMPT ARM
Apr 26 18:49:25 rbagain kernel: Modules linked in: cpufreq_stats nfsd nfs_acl rpcsec_gss_krb5 auth_rpcgss oid_registry nfsv4 dns_res
Apr 26 18:49:25 rbagain kernel: CPU: 0 PID: 841 Comm: python Not tainted 3.18.0-trunk-rpi #1 Debian 3.18.5-1~exp1+rpi19
Apr 26 18:49:25 rbagain kernel: task: dd003200 ti: dc71e000 task.ti: dc71e000
Apr 26 18:49:25 rbagain kernel: PC is at w1_slave_show+0x2d8/0x398 [w1_therm]
Apr 26 18:49:25 rbagain kernel: LR is at vsnprintf+0x294/0x414
Apr 26 18:49:25 rbagain kernel: pc : [<bf02336c>]    lr : [<c02c8544>]    psr: 80000013
                                sp : dc71fe08  ip : bf0235e0  fp : dc71fe54
Apr 26 18:49:25 rbagain kernel: r10: dc71fe27  r9 : 00000017  r8 : dc71fe27
Apr 26 18:49:25 rbagain kernel: r7 : dd3d4650  r6 : dd9e7000  r5 : 00000fe5  r4 : 00000000
Apr 26 18:49:25 rbagain kernel: r3 : 00000000  r2 : 1007ff7f  r1 : 464b0129  r0 : 0000000d
Apr 26 18:49:25 rbagain kernel: Flags: Nzcv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
Apr 26 18:49:25 rbagain kernel: Control: 00c5387d  Table: 1d3e0008  DAC: 00000015
Apr 26 18:49:25 rbagain kernel: Process python (pid: 841, stack limit = 0xdc71e1b0)
Apr 26 18:49:25 rbagain kernel: Stack: (0xdc71fe08 to 0xdc720000)
Apr 26 18:49:25 rbagain kernel: fe00:                   bf0235e8 dc71fe18 00000001 dc5a1c94 dc949040 297a41cc
Apr 26 18:49:25 rbagain kernel: fe20: 7f464b01 171007ff c011ed24 dc7dd600 bf023704 ddbe4200 00000fff 00001000
Apr 26 18:49:25 rbagain kernel: fe40: dd9e7000 c0575284 dc71fe6c dc71fe58 c0336928 bf0230a0 dc7dd600 dd3d4658
Apr 26 18:49:25 rbagain kernel: fe60: dc71fe9c dc71fe70 c01bba34 c0336908 c01bb998 00002000 dc71fec0 dc7dd600
Apr 26 18:49:25 rbagain kernel: fe80: dd029b40 00000001 00000001 dc71ff78 dc71feac dc71fea0 c01ba2dc c01bb9a4
Apr 26 18:49:25 rbagain kernel: fea0: dc71fefc dc71feb0 c016d970 c01ba2b4 dd029b48 00000000 dc7dd630 be993744
Apr 26 18:49:25 rbagain kernel: fec0: 00000000 00000000 dc71fefc dc71fed8 c0240000 ddbe4200 be993744 be993744
Apr 26 18:49:25 rbagain kernel: fee0: dc71ff78 00002000 00002000 be993744 dc71ff3c dc71ff00 c01badf0 c016d7b8
Apr 26 18:49:25 rbagain kernel: ff00: 571f9b6c 00000000 00000022 00000003 00000000 dd029b40 be993744 dc71e000
Apr 26 18:49:25 rbagain kernel: ff20: dc71ff78 00002000 dc71e000 be993744 dc71ff74 dc71ff40 c01498f4 c01bacd8
Apr 26 18:49:25 rbagain kernel: ff40: dc71ff5c dc71ff50 c0166930 00000000 00000000 dd029b40 dd029b40 00002000
Apr 26 18:49:25 rbagain kernel: ff60: dc71e000 be993744 dc71ffa4 dc71ff78 c0149a3c c0149864 00000000 00000000
Apr 26 18:49:25 rbagain kernel: ff80: 00000000 00002000 ffffffff 00000003 c000f884 00000000 00000000 dc71ffa8
Apr 26 18:49:25 rbagain kernel: ffa0: c000f640 c01499fc 00000000 00002000 00000004 be993744 00002000 00000000
Apr 26 18:49:25 rbagain kernel: ffc0: 00000000 00002000 ffffffff 00000003 020ca738 00002000 00002000 be993744
Apr 26 18:49:25 rbagain kernel: ffe0: 00000000 be9936a4 b6d9b234 b6df290c 60000010 00000004 00000000 00000000
Apr 26 18:49:25 rbagain kernel: [<bf02336c>] (w1_slave_show [w1_therm]) from [<c0336928>] (dev_attr_show+0x2c/0x58)
Apr 26 18:49:25 rbagain kernel: [<c0336928>] (dev_attr_show) from [<c01bba34>] (sysfs_kf_seq_show+0x9c/0x120)
Apr 26 18:49:25 rbagain kernel: [<c01bba34>] (sysfs_kf_seq_show) from [<c01ba2dc>] (kernfs_seq_show+0x34/0x38)
Apr 26 18:49:25 rbagain kernel: [<c01ba2dc>] (kernfs_seq_show) from [<c016d970>] (seq_read+0x1c4/0x4a0)
Apr 26 18:49:25 rbagain kernel: [<c016d970>] (seq_read) from [<c01badf0>] (kernfs_fop_read+0x124/0x16c)
Apr 26 18:49:25 rbagain kernel: [<c01badf0>] (kernfs_fop_read) from [<c01498f4>] (vfs_read+0x9c/0x198)
Apr 26 18:49:25 rbagain kernel: [<c01498f4>] (vfs_read) from [<c0149a3c>] (SyS_read+0x4c/0x98)
Apr 26 18:49:25 rbagain kernel: [<c0149a3c>] (SyS_read) from [<c000f640>] (ret_fast_syscall+0x0/0x30)
Apr 26 18:49:25 rbagain kernel: Code: eb4a9705 e5173004 e51b2031 e51b1035 (e5832004)
Apr 26 18:49:25 rbagain kernel: ---[ end trace 028330aecbc655fa ]---

Some basic system info:

$ uname -a
Linux rbagain 3.18.0-trunk-rpi #1 PREEMPT Debian 3.18.5-1~exp1+rpi19 (2015-08-08) armv6l GNU/Linux

$ cat /etc/modules
bcm2708-rng
w1-therm
w1-gpio

source: http://abyz.co.uk/rpi/pigpio/code/DHTXXD.zip

DHTXXD.h : 2015-11-15
DHTXXD.c : 2016-02-16

$ pigpiod -v
51