--0313--
ken 不好意思 请教一下 之前你有交过我 在没有coredump的情况下 可以用gdb直接载入ko.debug, 然后dis -l register_bcache, 我记得使用方式是不是这样, 不过我现在dis -l出现错误^^"
[root@k22 ~]# gdb /usr/lib/debug/lib/modules/4.18.0-147.5.1.el8_1.5es.1.x86_64/kernel/drivers/md/bcache/escache.ko.debug
...
(gdb) dis -l register_bcache
negative value
ken.kuo profile image
郭冠禹
4:15 PM
disass register_bcache
kc.chuang profile image
庄凯杰
4:17 PM
那如果我要看 bch_cached_dev_store+0x23/0xb0 [escache] 这个function的哪一行呢?
[root@node-1 ~]# cat /proc/8217/stack
[<0>] bch_cached_dev_store+0x23/0xb0 [escache]
[<0>] kernfs_fop_write+0x116/0x190
[<0>] vfs_write+0xa5/0x1a0
[<0>] ksys_write+0x4f/0xb0
[<0>] do_syscall_64+0x5b/0x1b0
[<0>] entry_SYSCALL_64_after_hwframe+0x65/0xca
[<0>] 0xffffffffffffffff
New Messages
ken.kuo profile image
郭冠禹
4:18 PM
l *(bch_cached_dev_store+0x23)
--
[ 257.059789] BUG: unable to handle kernel NULL pointer dereference at 00000000000009b0
[ 257.059939] IP: [<ffffffffc0490484>] register_bcache+0x1164/0x1360 [escache]
[ 257.060098] PGD 22d23b067 PUD 229358067 PMD 0
[ 257.060174] Oops: 0000 [#1] SMP
[ 257.060241] Modules linked in: veth nf_conntrack_netlink xt_statistic xt_nat xt_recent xt_conntrack ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6_tables ip_set nfnetlink xt_addrtype ipt_MASQUERADE nf_nat_masquerade_ipv4 xt_comment iptable_filter xt_mark iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack dm_thin_pool dm_persistent_data dm_bio_prison dm_bufio ext4 mbcache jbd2 escache snd_hda_codec_generic snd_hda_intel ppdev snd_hda_codec snd_hda_core iosf_mbi crc32_pclmul pcspkr snd_hwdep ghash_clmulni_intel snd_seq snd_seq_device aesni_intel lrw gf128mul snd_pcm glue_helper ablk_helper cryptd sg snd_timer joydev virtio_rng snd soundcore parport_pc virtio_balloon i2c_piix4 parport br_netfilter bridge stp llc ip_tables xfs libcrc32c sd_mod crc_t10dif crct10dif_generic
[ 257.061081] ata_generic pata_acpi virtio_console virtio_net virtio_blk qxl drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm ahci libahci drm ata_piix libata crct10dif_pclmul crct10dif_common crc32c_intel floppy serio_raw i2c_core virtio_pci virtio_ring virtio dm_mirror dm_region_hash dm_log dm_mod
[ 257.061438] CPU: 0 PID: 22740 Comm: bcache-register Not tainted 3.10.0-693.11.1.el7.es.12.x86_64 #1
[ 257.061528] Hardware name: Red Hat KVM, BIOS 1.10.2-3.el7.centos.es.1 04/01/2014
[ 257.061604] task: ffff8801b829ef20 ti: ffff88022d250000 task.ti: ffff88022d250000
[ 257.061682] RIP: 0010:[<ffffffffc0490484>] [<ffffffffc0490484>] register_bcache+0x1164/0x1360 [escache]
[ 257.061789] RSP: 0018:ffff88022d253de8 EFLAGS: 00010202
[ 257.061873] RAX: ffff88022ee20000 RBX: ffff880084254000 RCX: ffff8800843a0000
[ 257.061960] RDX: ffff8800843a0000 RSI: ffff88022ee20000 RDI: 0000000000000001
[ 257.062032] RBP: ffff88022d253e98 R08: 0000000000000000 R09: ffffffff81211a1d
[ 257.062105] R10: ffff88023fc19cc0 R11: ffffea0002109400 R12: ffffffffc049f180
[ 257.062177] R13: ffff88017f828d00 R14: ffffffff81718380 R15: 000000000000000a
[ 257.062259] FS: 00007f89ff367740(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000
[ 257.062345] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 257.062412] CR2: 00000000000009b0 CR3: 0000000229b2b000 CR4: 00000000003406f0
[ 257.062510] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 257.062600] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 257.062676] Stack:
[ 257.062722] 0000000200000000 ffff88023ffd8000 ffff88023ffd7000 0000000000000000
[ 257.062813] 0000000000000000 00000000975430b0 ffffffff85e579c0 00000000000080d0
[ 257.062907] 000000000000000a 0000000000000000 ffff88007dec51d0 fffffffffffffff0
[ 257.062991] Call Trace:
[ 257.063075] [<ffffffff811d1098>] ? alloc_pages_current+0x98/0x110
[ 257.063162] [<ffffffff81324bff>] kobj_attr_store+0xf/0x20
[ 257.063258] [<ffffffff81280046>] sysfs_write_file+0xc6/0x140
[ 257.063333] [<ffffffff81200a9d>] vfs_write+0xbd/0x1e0
[ 257.063404] [<ffffffff812018af>] SyS_write+0x7f/0xe0
[ 257.063484] [<ffffffff816b50c9>] system_call_fastpath+0x16/0x1b
[ 257.063570] Code: 4a d0 48 83 e8 30 48 81 fa b0 f1 49 c0 0f 84 59 01 00 00 48 89 c6 48 89 ca 0f b7 ba 34 04 00 00 4c 8b 82 40 0c 00 00 85 ff 74 3a <4d> 3b a8 b0 09 00 00 0f 84 0c 01 00 00 44 8d 47 ff 31 ff 49 c1
[ 257.063927] RIP [<ffffffffc0490484>] register_bcache+0x1164/0x1360 [escache]
[ 257.064006] RSP <ffff88022d253de8>
[ 257.064057] CR2: 00000000000009b0
起动crash
crash /usr/lib/debug/lib/modules/3.10.0-693.11.1.el7.es.12.x86_64/vmlinux /var/crash/127.0.0.1-2019-03-05-18\:07\:19/vmcore
bt 印出出问题时的backtrace
如果要在disassemble的是module，印出对应的c code是那一行，要先load module进来
mod -s escache
disassemble某个address，最后面是要disassemble多少行
dis -l ffffffffc0490484 1
disassemble某个function
dis -l register_bcache
crash> dis -l ffffffffc0490484
/usr/src/debug/kernel-3.10.0-693.11.1.el7/linux-3.10.0-693.11.1.el7.es.12.x86_64/drivers/md/bcache/super.c: 1989
0xffffffffc0490484 <register_bcache+4452>: cmp 0x9b0(%r8),%r13
4452=0x1164，所以可以透過dis -l register_bcache, 然後搜尋4452就可以找到上面這行
或者透過dump"IP: [<ffffffffc0490484>] register_bcache+0x1164/0x1360 [escache]"這行也直接告訴你是死在ffffffffc0490484，所以可以直接dis -l ffffffffc0490484
要看structure的define可以用struct，加上-o可以看到member的offset，struct后面加上address，可以直接把address的内容套到structure上
struct -o cache
