On Tue, Aug 13, 2019 at 02:41:55PM +0200, Vasily Gorbik wrote: > On Tue, Aug 13, 2019 at 07:19:24PM +1000, Stephen Rothwell wrote: > > Merging security/next-testing (a4848e06f9af Merge branch 'next-lockdown' into next-testing) > > CONFLICT (content): Merge conflict in kernel/trace/trace_kprobe.c > > CONFLICT (content): Merge conflict in fs/tracefs/inode.c > > Applying: early_security_init() needs a stub got !CONFIG_SECURITY > > Hi all, > > next-lockdown causes panic on s390 when doing: > cat /sys/kernel/debug/tracing/events/syscalls/sys_enter_read/id > > [ 3972.384027] Unable to handle kernel pointer dereference in virtual kernel address space > [ 3972.384031] Failing address: 0000000000000000 TEID: 0000000000000887 > [ 3972.384032] Fault in home space mode while using kernel ASCE. > [ 3972.384033] AS:00000000744cc007 R3:00000001fffd0007 S:00000001fffd6000 P:000000000000013d > [ 3972.384051] Oops: 0004 ilc:1 [#1] SMP > [ 3972.384053] Modules linked in: binfmt_misc(E) dm_crypt(E) lcs(E) ctcm(E) fsm(E) algif_skcipher(E) af_alg(E) nfsv3(E) nfs_acl(E) nfs(E) lockd(E) grace(E) sctp(E) quota_v2(E) quota_tree(E) ntfs(E) vfat(E) fat(E) overlay(E) loop(E) dm_service_time(E) kvm(E) xt_CHECKSUM(E) xt_MASQUERADE(E) xt_tcpudp(E) ip6t_rpfilter(E) ip6t_REJECT(E) nf_reject_ipv6(E) ipt_REJECT(E) nf_reject_ipv4(E) xt_conntrack(E) ip6table_nat(E) ip6table_mangle(E) ip6table_raw(E) tun(E) ip6table_security(E) bridge(E) iptable_nat(E) nf_nat(E) stp(E) llc(E) iptable_mangle(E) iptable_raw(E) iptable_security(E) nf_conntrack(E) nf_defrag_ipv6(E) nf_defrag_ipv4(E) ip_set(E) nfnetlink(E) ip6table_filter(E) ip6_tables(E) iptable_filter(E) ip_tables(E) x_tables(E) sunrpc(E) dm_multipath(E) dm_mod(E) scsi_dh_rdac(E) scsi_dh_emc(E) scsi_dh_alua(E) s390_trng(E) ghash_s390(E) prng(E) aes_s390(E) des_s390(E) des_generic(E) sha512_s390(E) sha1_s390(E) vfio_ccw(E) vfio_mdev(E) mdev(E) vfio_iommu_type1(E) vfio(E) eadm_sch(E) sch_fq_codel(E) > [ 3972.384076] sha256_s390(E) sha_common(E) pkey(E) zcrypt(E) rng_core(E) autofs4(E) [last unloaded: dummy_del_mod] > [ 3972.384084] CPU: 17 PID: 45118 Comm: psvc-ioctl-bpf1 Tainted: G OE 5.3.0-20190813.rc4.git0.8e72ac275c63.301.fc30.s390x+next #1 > [ 3972.384086] Hardware name: IBM 3906 M04 704 (LPAR) > [ 3972.384087] Krnl PSW : 0704c00180000000 0000000000000000 (0x0) > [ 3972.384090] R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 RI:0 EA:3 > [ 3972.384103] Krnl GPRS: 000003e004c0fb90 0000000000000000 00000001f912abf0 0000000197b36800 > [ 3972.384104] 0000000197b36810 0000000000000001 0000000100000000 0000000197b36810 > [ 3972.384105] 00000000736ae3a0 0000000100000000 00000001f912abf0 0000000197b36800 > [ 3972.384106] 000000013aff0000 0000000073c625a8 00000000734a1486 000003e004c0fbc8 > [ 3972.384110] Krnl Code:>0000000000000000: 0000 illegal > 0000000000000002: 0000 illegal > 0000000000000004: 0000 illegal > 0000000000000006: 0000 illegal > 0000000000000008: 0000 illegal > 000000000000000a: 0000 illegal > 000000000000000c: 0000 illegal > 000000000000000e: 0000 illegal > [ 3972.384116] Call Trace: > [ 3972.384122] ([<00000000734a1486>] do_dentry_open+0x206/0x3c0) > [ 3972.384125] [<00000000734b8c1e>] do_last+0x16e/0x918 > [ 3972.384126] [<00000000734b944e>] path_openat+0x86/0x2b8 > [ 3972.384128] [<00000000734baa64>] do_filp_open+0x7c/0xf8 > [ 3972.384129] [<00000000734a3484>] do_sys_open+0x18c/0x258 > [ 3972.384134] [<0000000073c457cc>] system_call+0xd8/0x2c8 > [ 3972.384135] Last Breaking-Event-Address: > [ 3972.384139] [<00000000736ae3fa>] default_open_file+0x5a/0x78 > [ 3972.384141] Kernel panic - not syncing: Fatal exception: panic_on_oops > > Which correspond to: > fs/tracefs/inode.c:46 > static int default_open_file(struct inode *inode, struct file *filp) > 45 real_fops = dentry->d_fsdata; > 46 return real_fops->open(inode, filp); > > Commit which introduces the problem: > commit 757ff7244358406dd16a7f5f623ca40ed27c603c > Author: Matthew Garrett <matthewgarrett@xxxxxxxxxx> > AuthorDate: Wed Aug 7 17:07:19 2019 -0700 > Commit: James Morris <jmorris@xxxxxxxxx> > CommitDate: Fri Aug 9 22:23:58 2019 -0700 > > tracefs: Restrict tracefs when the kernel is locked down > > Tracefs may release more information about the kernel than desirable, so > restrict it when the kernel is locked down in confidentiality mode by > preventing open(). > > Signed-off-by: Matthew Garrett <mjg59@xxxxxxxxxx> > Reviewed-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> > Signed-off-by: James Morris <jmorris@xxxxxxxxx> > --- > fs/tracefs/inode.c | 40 +++++++++++++++++++++++++++++++++++++++- > include/linux/security.h | 1 + > security/lockdown/lockdown.c | 1 + > 3 files changed, 41 insertions(+), 1 deletion(-) > > Using default s390 config, where > # CONFIG_SECURITY_LOCKDOWN_LSM is not set Hm, this actually looks like a general problem. Please, consider the following patch, if it makes sense. It fixes the problem for me. -- ⣿⣿⣿⣿⢋⡀⣀⠹⣿⣿⣿⣿ ⣿⣿⣿⣿⠠⣶⡦⠀⣿⣿⣿⣿ ⣿⣿⣿⠏⣴⣮⣴⣧⠈⢿⣿⣿ ⣿⣿⡏⢰⣿⠖⣠⣿⡆⠈⣿⣿ ⣿⢛⣵⣄⠙⣶⣶⡟⣅⣠⠹⣿ ⣿⣜⣛⠻⢎⣉⣉⣀⠿⣫⣵⣿
