我为Nexus 5编写了一个内核模块（参见下面的代码），通过kprobes跟踪一些系统调用（我已经构建了一个为此启用了kprobes的自定义内核）。
有时，通过rmmod卸载模块时，我的手机会冻结并重新启动。试图找出错误的根本原因，现在在我的模块中除了为syscall do_fork注册jprobe的代码之外什么也没留下（但是其他探测函数也会发生错误）并在卸载时取消注册（因此，我认为它是可能是ARM上的kprobes错误而不是Android特定问题）。也许有人能指出我在kprobes中的一个已知错误？
关于内核恐慌的日志告诉我一些分页问题Unable to handle kernel paging request at virtual address c0193a2c，其中c0193a2c实际上是do_fork的地址。
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/kprobes.h>
long trace_do_fork(unsigned long clone_flags, unsigned long stack_start,
struct pt_regs *regs, unsigned long stack_size,
int __user *parent_tidptr, int __user *child_tidptr)
{
jprobe_return();
return 0;
}
#define CREATE_JPROBE(victim, target) \
static struct jprobe jp_##victim = { \
.entry = (kprobe_opcode_t *) target, \
.kp = { \
.symbol_name = #victim, \
}, \
}
CREATE_JPROBE(do_fork, trace_do_fork);
#define NUM_PROBES 1
static struct jprobe *jprobes[NUM_PROBES] = {
&jp_do_fork,
};
static int __init droidtracer_init(void)
{
int err;
/* plant jprobes */
err = register_jprobes(jprobes, NUM_PROBES);
if (err) {
printk(KERN_ERR "RV; register_jprobes failed = %d\n", err);
return err;
}
printk(KERN_INFO "RV; planted %d jprobes\n", NUM_PROBES);
return 0;
}
static void __exit droidtracer_exit(void)
{
unregister_jprobes(jprobes, NUM_PROBES);
}
module_init(droidtracer_init);
module_exit(droidtracer_exit);
以下是我的Nexus 5上cat /proc/last_kmsg的输出：
[ 1967.788836] RV; planted 1 jprobes
[ 1967.908095] init: untracked pid 15957 exited with status 17
[ 1967.987314] type=1400 audit(1449702053.652:53): avc: denied { write } for pid=16008 comm="app_process32_o" name="system@framework@boot.art" dev="dm-0" ino=491522 scontext=u:r:shell:s0 tcontext=u:object_r:dalvikcache_data_file:s0 tclass=file
[ 1968.102799] init: untracked pid 16001 exited with status 52
[ 1968.122856] init: untracked pid 15960 exited with status 0
[ 1968.330685] init: untracked pid 16008 exited with status 0
[ 1969.106371] Unable to handle kernel paging request at virtual address c0193a2c
[ 1969.106418] pgd = c0004000
[ 1969.106489] [c0193a2c] *pgd=0001141e(bad)
[ 1969.106602] Internal error: Oops: 80d [#1] PREEMPT SMP ARM
[ 1969.106642] Modules linked in: droidtracer(O-) [last unloaded: droidtracer]
[ 1969.106821] CPU: 3 Tainted: G O (3.4.0-g5170b88 #23)
[ 1969.106897] PC is at __patch_text+0x34/0x58
[ 1969.106939] LR is at mem_text_address_writeable+0xac/0xc4
[ 1969.106980] pc : [<c0a4db78>] lr : [<c01166a4>] psr: 20000093
[ 1969.106982] sp : e8d43ea0 ip : c0193000 fp : e8d43ebc
[ 1969.107088] r10: 00000001 r9 : dae8fde4 r8 : 00000001
[ 1969.107158] r7 : a0000013 r6 : dae8fe54 r5 : e1a0c00d r4 : c0193a2c
[ 1969.107197] r3 : c113a4a4 r2 : c0007000 r1 : c0193a2c r0 : c0193000
[ 1969.107238] Flags: nzCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel
[ 1969.107310] Control: 10c5787d Table: 3558006a DAC: 00000015
[ 1969.107350]
[ 1969.107351] PC: 0xc0a4daf8:
[ 1969.107455] daf8 e89da9f8 e592300c e3a04002 e1a00004 e5813004 e89da9f8 e592300c e12fff33
[ 1969.107818] db18 e1a04000 e1a00004 e89da9f8 e592200c eaffff9c e1a02006 e3a07001 eaffff99
[ 1969.108213] db38 e1a04005 eaffffd1 c0b00670 e1a0c00d e92dd830 e24cb004 e24dd008 e1a04000
[ 1969.108575] db58 e24b0018 e1a05001 ebdb228f e1a00004 ebdb22a2 e30a34a4 e34c3113 e1a01004
[ 1969.108971] db78 e4815004 e1a00004 e5933010 e12fff33 ebdb22cb e24b0018 ebdb228e e24bd014
[ 1969.109340] db98 e89da830 e1a0c00d e92dd800 e24cb004 ebffffe5 e89da800 e1a0c00d e92dd800
[ 1969.109738] dbb8 e24cb004 e52de004 e8bd4000 e5902030 e5900014 e3c234ff e3120401 e1a03103
[ 1969.110132] dbd8 e2032402 e2622000 e1823003 12802004 e2800008 15812038 e0803003 e581303c
[ 1969.110504]
[ 1969.110505] LR: 0xc0116624:
[ 1969.110610] 6624 e3a01000 e592200c e5c31014 e59221f0 e5922024 389da818 e59f1074 e1500001
[ 1969.111006] 6644 289da818 e1a01aa0 e3100601 e3c00eff e59f4058 e0822181 e3c0000f e583000c
[ 1969.111375] 6664 12820004 01a00002 e5832008 e5901000 15830008 e201c003 e5832004 e35c0002
[ 1969.111771] 6684 e5831010 189da818 e3c11902 e5801000 ee072f3a f57ff04f e594000c ebffda1c
[ 1969.112166] 66a4 e3a03001 e5c43014 e89da818 c0008000 c11ff920 c0b00000 e1a0c00d e92dd800
[ 1969.112534] 66c4 e24cb004 e52de004 e8bd4000 e59f302c e5d32014 e3520000 089da800 e5931008
[ 1969.112927] 66e4 e5930010 e5932004 e5810000 ee072f3a f57ff04f e593000c ebffda05 e89da800
[ 1969.113324] 6704 c11ff920 e1a0c00d e92dd830 e24cb004 e24dd008 e52de004 e8bd4000 e1a04000
[ 1969.113723]
[ 1969.113724] SP: 0xe8d43e20:
[ 1969.113797] 3e20 c116efa0 c113c0d8 e8d43ee4 c0a4db78 20000093 ffffffff e8d43e8c 00000001
[ 1969.114190] 3e40 dae8fde4 00000001 e8d43ebc e8d43e58 c0a4c618 c010022c c0193000 c0193a2c
[ 1969.114558] 3e60 c0007000 c113a4a4 c0193a2c e1a0c00d dae8fe54 a0000013 00000001 dae8fde4
[ 1969.114950] 3e80 00000001 e8d43ebc c0193000 e8d43ea0 c01166a4 c0a4db78 20000093 ffffffff
[ 1969.115344] 3ea0 dae8df20 20000093 dae8fe40 00000003 e8d43ecc e8d43ec0 c0a4cabc c0a4db50
[ 1969.115739] 3ec0 e8d43ef4 e8d43ed0 c01f18c4 c0a4caa4 00000001 e8d42000 c241bd24 00000000
[ 1969.116103] 3ee0 dae8fe40 c01f17d8 e8d43fbc e8d43ef8 c01f1548 c01f17e4 c0a4ab08 c01c1eac
[ 1969.116497] 3f00 00000000 c241bd2c 00000000 00000000 618fcdfb 000001ca 00000001 c0a4b040
[ 1969.116894]
[ 1969.116895] IP: 0xc0192f80:
[ 1969.116967] 2f80 e58732c0 e58732bc e58731ec e58731f0 e59c300c e59301ec e3500000 0a00000c
[ 1969.117366] 2fa0 e3140c01 0a00003d e2803028 e1932f9f e2822001 e1831f92 e3310000 1afffffa
[ 1969.117763] 2fc0 e3a03000 e580316c e5803170 e58701ec e58701f0 e1a00004 e1a01007 eb00a279
[ 1969.118129] 2fe0 e250a000 13a09000 0a000033 e59701ec e3500000 0a000000 ebfffca5 e51bc040
[ 1969.118527] 3000 e35c0000 1a000004 e30c1ec0 e34c1126 e591000c e59713c8 eb036498 e59703cc
[ 1969.118924] 3020 ebfffe62 e1a00007 eb042de4 e1a00007 eb00166d eaffffa8 e1a0000a eb042dfd
[ 1969.119284] 3040 e3500000 e58703bc 1affffbb e3e0a00b e3a09000 eafffff4 e30c1ec0 e34c1126
[ 1969.119648] 3060 e591001c e3a010d0 eb0362da f57ff05f e3500000 e58703cc 0a000223 e51bc03c
[ 1969.120044]
[ 1969.120045] FP: 0xe8d43e3c:
[ 1969.120118] 3e3c 00000001 dae8fde4 00000001 e8d43ebc e8d43e58 c0a4c618 c010022c c0193000
[ 1969.120513] 3e5c c0193a2c c0007000 c113a4a4 c0193a2c e1a0c00d dae8fe54 a0000013 00000001
[ 1969.120907] 3e7c dae8fde4 00000001 e8d43ebc c0193000 e8d43ea0 c01166a4 c0a4db78 20000093
[ 1969.121275] 3e9c ffffffff dae8df20 20000093 dae8fe40 00000003 e8d43ecc e8d43ec0 c0a4cabc
[ 1969.121646] 3ebc c0a4db50 e8d43ef4 e8d43ed0 c01f18c4 c0a4caa4 00000001 e8d42000 c241bd24
[ 1969.122045] 3edc 00000000 dae8fe40 c01f17d8 e8d43fbc e8d43ef8 c01f1548 c01f17e4 c0a4ab08
[ 1969.122442] 3efc c01c1eac 00000000 c241bd2c 00000000 00000000 618fcdfb 000001ca 00000001
[ 1969.122808] 3f1c c0a4b040 c1131740 c1131740 00001f21 00000000 c112e450 c1131740 00000000
[ 1969.123204]
[ 1969.123205] R0: 0xc0192f80:
[ 1969.123308] 2f80 e58732c0 e58732bc e58731ec e58731f0 e59c300c e59301ec e3500000 0a00000c
[ 1969.123673] 2fa0 e3140c01 0a00003d e2803028 e1932f9f e2822001 e1831f92 e3310000 1afffffa
[ 1969.124068] 2fc0 e3a03000 e580316c e5803170 e58701ec e58701f0 e1a00004 e1a01007 eb00a279
[ 1969.124464] 2fe0 e250a000 13a09000 0a000033 e59701ec e3500000 0a000000 ebfffca5 e51bc040
[ 1969.124827] 3000 e35c0000 1a000004 e30c1ec0 e34c1126 e591000c e59713c8 eb036498 e59703cc
[ 1969.125223] 3020 ebfffe62 e1a00007 eb042de4 e1a00007 eb00166d eaffffa8 e1a0000a eb042dfd
[ 1969.125618] 3040 e3500000 e58703bc 1affffbb e3e0a00b e3a09000 eafffff4 e30c1ec0 e34c1126
[ 1969.126013] 3060 e591001c e3a010d0 eb0362da f57ff05f e3500000 e58703cc 0a000223 e51bc03c
[ 1969.126383]
[ 1969.126384] R1: 0xc01939ac:
[ 1969.126489] 39ac 1afffffa e587a454 eafffdcb c11cbe80 c11688f0 c1168f54 c1134040 c0d6c9ac
[ 1969.126856] 39cc c1142f38 c113c0d8 c112e5c0 c11cceb8 c0d6c96c c126cee4 c0199c94 c0d6c980
[ 1969.127253] 39ec c0d6c994 e1a0c00d e92dd800 e24cb004 e52de004 e8bd4000 e1a0200d e3c23d7f
[ 1969.127649] 3a0c e3a01000 e3c3303f e1a02001 e593c00c e58c029c e593000c eb0079f6 e89da800
[ 1969.128050] 3a2c e1a0c00d e92dddf0 e24cb004 e24dd020 e52de004 e8bd4000 e3100201 e1a04000
[ 1969.128419] 3a4c e1a06001 e1a07002 e1a05003 0a00000d e3100801 1a00005c e3a00015 eb002f48
[ 1969.128817] 3a6c e3500000 0a00009c e3a00007 eb002f44 e3500000 0a000098 e3a00006 eb002f40
[ 1969.129217] 3a8c e3500000 0a000094 e5978040 e218800f 13a08000 1a000012 e3140502 1a000010
[ 1969.129587]
[ 1969.129588] R2: 0xc0006f80:
[ 1969.129662] 6f80 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 1969.130063] 6fa0 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 1969.130431] 6fc0 349ec811 349ecc11 00000000 00000000 00000000 00000000 00000000 00000000
[ 1969.130828] 6fe0 00000000 00000000 00000000 00000000 00000000 00000000 36be7811 36be7c11
[ 1969.131223] 7000 0001141e 0011140e 0021940e 0031940e 0041940e 0051940e 0061940e 0071940e
[ 1969.131587] 7020 0081940e 0091940e 00a1940e 00b1941e 00c1941e 00d1941e 00e1941e 00f1941e
[ 1969.131955] 7040 0101940e 0111141e 0121141e 0131141e 0141141e 0151141e 0161141e 0171141e
[ 1969.132352] 7060 0181141e 0191141e 01a1141e 01b1141e 01c1141e 01d1141e 01e1141e 01f1141e
[ 1969.132748]
[ 1969.132749] R3: 0xc113a424:
[ 1969.132821] a424 6f0565ba 31608756 fbbc260d 3ab7828b f06b23d0 ae0ec13c 64d26067 20dba45a
[ 1969.133212] a444 36c8dc43 292974a6 331e896e d0b7bc08 06876874 d288e84f 1672f9f9 9cc6ff8c
[ 1969.133578] a464 178284ea 4f454bb9 9fa41d71 91e87642 cd987452 16bf87ac 124bab00 00000001
[ 1969.133949] a484 00000000 20fd1972 c010d2f0 ffffffff 00000009 0007b0d7 c01184c0 c0118474
[ 1969.134351] a4a4 c0118220 c01182cc c01182e4 c01182e4 c01182e8 c01182e8 c0118364 c011844c
[ 1969.134752] a4c4 c011845c c011839c c01183e4 c0118418 00000022 ffffffff 00000000 fa002000
[ 1969.135119] a4e4 fa003000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 1969.135516] a504 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 1969.135878]
[ 1969.135879] R4: 0xc01939ac:
[ 1969.135952] 39ac 1afffffa e587a454 eafffdcb c11cbe80 c11688f0 c1168f54 c1134040 c0d6c9ac
[ 1969.136351] 39cc c1142f38 c113c0d8 c112e5c0 c11cceb8 c0d6c96c c126cee4 c0199c94 c0d6c980
[ 1969.136747] 39ec c0d6c994 e1a0c00d e92dd800 e24cb004 e52de004 e8bd4000 e1a0200d e3c23d7f
[ 1969.137116] 3a0c e3a01000 e3c3303f e1a02001 e593c00c e58c029c e593000c eb0079f6 e89da800
[ 1969.137515] 3a2c e1a0c00d e92dddf0 e24cb004 e24dd020 e52de004 e8bd4000 e3100201 e1a04000
[ 1969.137879] 3a4c e1a06001 e1a07002 e1a05003 0a00000d e3100801 1a00005c e3a00015 eb002f48
[ 1969.138276] 3a6c e3500000 0a00009c e3a00007 eb002f44 e3500000 0a000098 e3a00006 eb002f40
[ 1969.138644] 3a8c e3500000 0a000094 e5978040 e218800f 13a08000 1a000012 e3140502 1a000010
[ 1969.139038]
[ 1969.139039] R5: 0xe1a0bf8d:
[ 1969.139112] bf8c 5d02005d 5d04000a 00203d20 3d205d10 77656e20 72724120 29287961 5d1c003b
[ 1969.139509] bfac 6977202c 74206874 66206568 6f6c6c6f 676e6977 74696b20 000a3a73 003b5d02
[ 1969.139870] bfcc 203b5d03 5b5d1000 746c6127 74786574 3d205d27 0d002720 63275b5d 27646966
[ 1969.140267] bfec 203d205d 5d0d0027 6574275b 5d277478 27203d20 57165211 ff6aff65 51105110
[ 1969.140636] c00c ff64ff64 54144f0f ff6aff65 55154e0d ff6bff63 510e4f0d ff64ff63 48055310
[ 1969.141036] c02c ff5bff66 55125512 ff68ff68 5412520f ff68ff65 520f5613 ff65ff69 510e5411
[ 1969.141431] c04c ff64ff67 5410510d ff65ff63 5512510d ff67ff63 500d5916 ff63ff6c 54115714
[ 1969.141799] c06c ff67ff6a 5412500d ff68ff63 59165512 ff6cff68 4f0d5310 ff63ff66 54115613
[ 1969.142201] c08c ff67ff69 53105512 ff66ff68 54125412 ff68ff68 53105412 ff66ff68 53105512
[ 1969.142601]
[ 1969.142603] R6: 0xdae8fdd4:
[ 1969.142676] fdd4 dae8fde0 c01f1944 c01f16ec c113b004 00000004 00000000 00000000 00000000
[ 1969.143074] fdf4 00000000 dae8fdf8 dae8fdf8 c0a49acc c116b588 c113b004 dae8fe40 dae8fe3c
[ 1969.143472] fe14 dae8fe20 c01f1a84 c01f1900 c0a4ca98 bf00a0f4 c113b004 c113b004 dae8fe74
[ 1969.143841] fe34 dae8fe40 c01f1ba8 c01f1a50 c0a4ca98 bf00a0f4 00000004 c113b004 00000003
[ 1969.144239] fe54 00000002 c113b004 bf00a0f4 c0a4ca98 00000000 dae8fe94 dae8fe78 c01f1c1c
[ 1969.144633] fe74 c01f1b04 c0b09a34 bf00a0f4 bf00a0f4 00000001 dae8fea4 dae8fe98 c0a4cc34
[ 1969.145028] fe94 c01f1bf4 dae8fec4 dae8fea8 c0a4ecf4 c0a4cc10 00000000 00000001 00000001
[ 1969.145392] feb4 bf00a0f4 dae8fee4 dae8fec8 c0a4f03c c0a4ec80 c0a49acc c0a49748 00000001
[ 1969.145787]
[ 1969.145788] R9: 0xdae8fd64:
[ 1969.145859] fd64 c112ed38 00000002 dae8e000 c113b004 c113b868 c112ed24 c112ed38 dae8e000
[ 1969.146259] fd84 c113c0d8 dae8fdac dae8fd98 c0a4afe4 c0a4a71c 00000002 00000004 dae8fddc
[ 1969.146656] fda4 dae8fdb0 c01f17c4 c0a4afb0 dae8fde4 c113b004 c01f17d8 dae8fe40 c01f17d8
[ 1969.147056] fdc4 bf00a0f0 dae8e000 00000000 dae8fe1c dae8fde0 c01f1944 c01f16ec c113b004
[ 1969.147422] fde4 00000004 00000000 00000000 00000000 00000000 dae8fdf8 dae8fdf8 c0a49acc
[ 1969.147822] fe04 c116b588 c113b004 dae8fe40 dae8fe3c dae8fe20 c01f1a84 c01f1900 c0a4ca98
[ 1969.148220] fe24 bf00a0f4 c113b004 c113b004 dae8fe74 dae8fe40 c01f1ba8 c01f1a50 c0a4ca98
[ 1969.148591] fe44 bf00a0f4 00000004 c113b004 00000003 00000002 c113b004 bf00a0f4 c0a4ca98
[ 1969.148958] Process migration/3 (pid: 16049, stack limit = 0xe8d422f0)
[ 1969.149029] Stack: (0xe8d43ea0 to 0xe8d44000)
[ 1969.149071] 3ea0: dae8df20 20000093 dae8fe40 00000003 e8d43ecc e8d43ec0 c0a4cabc c0a4db50
[ 1969.149144] 3ec0: e8d43ef4 e8d43ed0 c01f18c4 c0a4caa4 00000001 e8d42000 c241bd24 00000000
[ 1969.149216] 3ee0: dae8fe40 c01f17d8 e8d43fbc e8d43ef8 c01f1548 c01f17e4 c0a4ab08 c01c1eac
[ 1969.149257] 3f00: 00000000 c241bd2c 00000000 00000000 618fcdfb 000001ca 00000001 c0a4b040
[ 1969.149330] 3f20: c1131740 c1131740 00001f21 00000000 c112e450 c1131740 00000000 00000000
[ 1969.149403] 3f40: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 c01c0214
[ 1969.149475] 3f60: 00000000 00000001 00000000 dc961de4 dc961de0 00000013 00000013 00000000
[ 1969.149518] 3f80: 00000000 dc961dd0 c241bd24 20fd1972 00000013 dc961dd0 c241bd24 c01f1484
[ 1969.149592] 3fa0: 00000013 00000000 00000000 00000000 e8d43ff4 e8d43fc0 c01b5f58 c01f1490
[ 1969.149664] 3fc0: 00000000 c241bd24 00000000 00000000 e8d43fd0 e8d43fd0 00000000 dc961dd0
[ 1969.149736] 3fe0: c01b5ec0 c0107c20 00000000 e8d43ff8 c0107c20 c01b5ecc 00000000 00000000
[ 1969.149784] [<c0a4db78>] (__patch_text+0x34/0x58) from [<c0a4cabc>] (__arch_disarm_kprobe+0x24/0x2c)
[ 1969.149863] [<c0a4cabc>] (__arch_disarm_kprobe+0x24/0x2c) from [<c01f18c4>] (stop_machine_cpu_stop+0xec/0x11c)
[ 1969.149940] [<c01f18c4>] (stop_machine_cpu_stop+0xec/0x11c) from [<c01f1548>] (cpu_stopper_thread+0xc4/0x1a8)
[ 1969.150018] [<c01f1548>] (cpu_stopper_thread+0xc4/0x1a8) from [<c01b5f58>] (kthread+0x98/0xa4)
[ 1969.150096] [<c01b5f58>] (kthread+0x98/0xa4) from [<c0107c20>] (kernel_thread_exit+0x0/0x8)
[ 1969.150139] Code: ebdb22a2 e30a34a4 e34c3113 e1a01004 (e4815004)
[ 1969.150239] ---[ end trace a138dd63f3507951 ]---
[ 1969.150279] Kernel panic - not syncing: Fatal exception
[ 1970.712851] SMP: failed to stop secondary CPUs
[ 1971.713234] Rebooting in 5 seconds..
[ 1978.277336] SMP: failed to stop secondary CPUs
[ 1978.277440] Going down for restart now
[ 1978.278139] Calling SCM to disable SPMI PMIC arbiter
No errors detected
Boot info:
Last boot reason: kernel_panic