* BUG at /build/buildd/linux-3.13.0/fs/pnode.c:372!
@ 2014-10-06 13:29 Andrey Wagin
2014-10-06 18:19 ` Serge E. Hallyn
0 siblings, 1 reply; 5+ messages in thread
From: Andrey Wagin @ 2014-10-06 13:29 UTC (permalink / raw)
To: linux-fsdevel, LKML
Hi All,
Here is a small program, which triggers a bug. Is it interested for someone?
root@ubuntu:/home/avagin# cat nsenter.c
#define _GNU_SOURCE /* See feature_test_macros(7) */
#include <sched.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mount.h>
int main(int argc, char **argv)
{
int fd;
fd = open("/proc/self/ns/mnt", O_RDONLY);
if (fd < 0)
return 1;
umount2("/", MNT_DETACH);
if (setns(fd, CLONE_NEWNS))
return 1;
umount2("/", MNT_DETACH);
return 0;
}
root@ubuntu:/home/avagin# gcc nsenter.c -o nsenter
root@ubuntu:/home/avagin# ./nsenter
[ 260.548301] ------------[ cut here ]------------
[ 260.550941] kernel BUG at /build/buildd/linux-3.13.0/fs/pnode.c:372!
[ 260.552068] invalid opcode: 0000 [#1] SMP
[ 260.552068] Modules linked in: xt_CHECKSUM iptable_mangle xt_tcpudp
xt_addrtype xt_conntrack ipt_MASQUERADE iptable_nat nf_conntrack_ipv4
nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack bridge stp llc
dm_thin_pool dm_persistent_data dm_bufio dm_bio_prison iptable_filter
ip_tables x_tables crct10dif_pclmul crc32_pclmul ghash_clmulni_intel
binfmt_misc nfsd auth_rpcgss nfs_acl aesni_intel nfs lockd aes_x86_64
sunrpc fscache lrw gf128mul glue_helper ablk_helper cryptd serio_raw
ppdev parport_pc lp parport btrfs xor raid6_pq libcrc32c psmouse
floppy
[ 260.552068] CPU: 0 PID: 1723 Comm: nsenter Not tainted
3.13.0-30-generic #55-Ubuntu
[ 260.552068] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 260.552068] task: ffff8800376097f0 ti: ffff880074824000 task.ti:
ffff880074824000
[ 260.552068] RIP: 0010:[<ffffffff811e9483>] [<ffffffff811e9483>]
propagate_umount+0x123/0x130
[ 260.552068] RSP: 0018:ffff880074825e98 EFLAGS: 00010246
[ 260.552068] RAX: ffff88007c741140 RBX: 0000000000000002 RCX: ffff88007c741190
[ 260.552068] RDX: ffff88007c741190 RSI: ffff880074825ec0 RDI: ffff880074825ec0
[ 260.552068] RBP: ffff880074825eb0 R08: 00000000000172e0 R09: ffff88007fc172e0
[ 260.552068] R10: ffffffff811cc642 R11: ffffea0001d59000 R12: ffff88007c741140
[ 260.552068] R13: ffff88007c741140 R14: ffff88007c741140 R15: 0000000000000000
[ 260.552068] FS: 00007fd5c7e41740(0000) GS:ffff88007fc00000(0000)
knlGS:0000000000000000
[ 260.552068] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 260.552068] CR2: 00007fd5c7968050 CR3: 0000000070124000 CR4: 00000000000406f0
[ 260.552068] Stack:
[ 260.552068] 0000000000000002 0000000000000002 ffff88007c631000
ffff880074825ed8
[ 260.552068] ffffffff811dcfac ffff88007c741140 0000000000000002
ffff88007c741160
[ 260.552068] ffff880074825f38 ffffffff811dd12b ffffffff811cc642
0000000075640000
[ 260.552068] Call Trace:
[ 260.552068] [<ffffffff811dcfac>] umount_tree+0x20c/0x260
[ 260.552068] [<ffffffff811dd12b>] do_umount+0x12b/0x300
[ 260.552068] [<ffffffff811cc642>] ? final_putname+0x22/0x50
[ 260.552068] [<ffffffff811cc849>] ? putname+0x29/0x40
[ 260.552068] [<ffffffff811dd88c>] SyS_umount+0xdc/0x100
[ 260.552068] [<ffffffff8172aeff>] tracesys+0xe1/0xe6
[ 260.552068] Code: 89 50 08 48 8b 50 08 48 89 02 49 89 45 08 e9 72
ff ff ff 0f 1f 44 00 00 4c 89 e6 4c 89 e7 e8 f5 f6 ff ff 48 89 c3 e9
39 ff ff ff <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 66 66 66 66 90 55
b8 01
[ 260.552068] RIP [<ffffffff811e9483>] propagate_umount+0x123/0x130
[ 260.552068] RSP <ffff880074825e98>
[ 260.611451] ---[ end trace 11c33d85f1d4c652 ]---
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: BUG at /build/buildd/linux-3.13.0/fs/pnode.c:372! 2014-10-06 13:29 BUG at /build/buildd/linux-3.13.0/fs/pnode.c:372! Andrey Wagin @ 2014-10-06 18:19 ` Serge E. Hallyn 2014-10-06 19:30 ` Andrey Wagin 0 siblings, 1 reply; 5+ messages in thread From: Serge E. Hallyn @ 2014-10-06 18:19 UTC (permalink / raw) To: Andrey Wagin; +Cc: linux-fsdevel, LKML Quoting Andrey Wagin (avagin@gmail.com): > Hi All, > > Here is a small program, which triggers a bug. Is it interested for someone? Yup, would diff --git a/fs/namespace.c b/fs/namespace.c index ef42d9b..ddef25d 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -3046,6 +3046,9 @@ static int mntns_install(struct nsproxy *nsproxy, void *ns) struct mnt_namespace *mnt_ns = ns; struct path root; + if (mnt_ns == nsproxy->mnt_ns) + return 0; + if (!ns_capable(mnt_ns->user_ns, CAP_SYS_ADMIN) || !ns_capable(current_user_ns(), CAP_SYS_CHROOT) || !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) fix it? > root@ubuntu:/home/avagin# cat nsenter.c > #define _GNU_SOURCE /* See feature_test_macros(7) */ > #include <sched.h> > #include <sys/types.h> > #include <sys/stat.h> > #include <fcntl.h> > #include <unistd.h> > #include <sys/mount.h> > > int main(int argc, char **argv) > { > int fd; > > fd = open("/proc/self/ns/mnt", O_RDONLY); > if (fd < 0) > return 1; > umount2("/", MNT_DETACH); > if (setns(fd, CLONE_NEWNS)) > return 1; > umount2("/", MNT_DETACH); > > return 0; > } > > root@ubuntu:/home/avagin# gcc nsenter.c -o nsenter > root@ubuntu:/home/avagin# ./nsenter > > > [ 260.548301] ------------[ cut here ]------------ > [ 260.550941] kernel BUG at /build/buildd/linux-3.13.0/fs/pnode.c:372! > [ 260.552068] invalid opcode: 0000 [#1] SMP > [ 260.552068] Modules linked in: xt_CHECKSUM iptable_mangle xt_tcpudp > xt_addrtype xt_conntrack ipt_MASQUERADE iptable_nat nf_conntrack_ipv4 > nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack bridge stp llc > dm_thin_pool dm_persistent_data dm_bufio dm_bio_prison iptable_filter > ip_tables x_tables crct10dif_pclmul crc32_pclmul ghash_clmulni_intel > binfmt_misc nfsd auth_rpcgss nfs_acl aesni_intel nfs lockd aes_x86_64 > sunrpc fscache lrw gf128mul glue_helper ablk_helper cryptd serio_raw > ppdev parport_pc lp parport btrfs xor raid6_pq libcrc32c psmouse > floppy > [ 260.552068] CPU: 0 PID: 1723 Comm: nsenter Not tainted > 3.13.0-30-generic #55-Ubuntu > [ 260.552068] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 > [ 260.552068] task: ffff8800376097f0 ti: ffff880074824000 task.ti: > ffff880074824000 > [ 260.552068] RIP: 0010:[<ffffffff811e9483>] [<ffffffff811e9483>] > propagate_umount+0x123/0x130 > [ 260.552068] RSP: 0018:ffff880074825e98 EFLAGS: 00010246 > [ 260.552068] RAX: ffff88007c741140 RBX: 0000000000000002 RCX: ffff88007c741190 > [ 260.552068] RDX: ffff88007c741190 RSI: ffff880074825ec0 RDI: ffff880074825ec0 > [ 260.552068] RBP: ffff880074825eb0 R08: 00000000000172e0 R09: ffff88007fc172e0 > [ 260.552068] R10: ffffffff811cc642 R11: ffffea0001d59000 R12: ffff88007c741140 > [ 260.552068] R13: ffff88007c741140 R14: ffff88007c741140 R15: 0000000000000000 > [ 260.552068] FS: 00007fd5c7e41740(0000) GS:ffff88007fc00000(0000) > knlGS:0000000000000000 > [ 260.552068] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 260.552068] CR2: 00007fd5c7968050 CR3: 0000000070124000 CR4: 00000000000406f0 > [ 260.552068] Stack: > [ 260.552068] 0000000000000002 0000000000000002 ffff88007c631000 > ffff880074825ed8 > [ 260.552068] ffffffff811dcfac ffff88007c741140 0000000000000002 > ffff88007c741160 > [ 260.552068] ffff880074825f38 ffffffff811dd12b ffffffff811cc642 > 0000000075640000 > [ 260.552068] Call Trace: > [ 260.552068] [<ffffffff811dcfac>] umount_tree+0x20c/0x260 > [ 260.552068] [<ffffffff811dd12b>] do_umount+0x12b/0x300 > [ 260.552068] [<ffffffff811cc642>] ? final_putname+0x22/0x50 > [ 260.552068] [<ffffffff811cc849>] ? putname+0x29/0x40 > [ 260.552068] [<ffffffff811dd88c>] SyS_umount+0xdc/0x100 > [ 260.552068] [<ffffffff8172aeff>] tracesys+0xe1/0xe6 > [ 260.552068] Code: 89 50 08 48 8b 50 08 48 89 02 49 89 45 08 e9 72 > ff ff ff 0f 1f 44 00 00 4c 89 e6 4c 89 e7 e8 f5 f6 ff ff 48 89 c3 e9 > 39 ff ff ff <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 66 66 66 66 90 55 > b8 01 > [ 260.552068] RIP [<ffffffff811e9483>] propagate_umount+0x123/0x130 > [ 260.552068] RSP <ffff880074825e98> > [ 260.611451] ---[ end trace 11c33d85f1d4c652 ]--- > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: BUG at /build/buildd/linux-3.13.0/fs/pnode.c:372! 2014-10-06 18:19 ` Serge E. Hallyn @ 2014-10-06 19:30 ` Andrey Wagin 2014-10-06 19:44 ` Serge E. Hallyn 0 siblings, 1 reply; 5+ messages in thread From: Andrey Wagin @ 2014-10-06 19:30 UTC (permalink / raw) To: Serge E. Hallyn; +Cc: linux-fsdevel, LKML 2014-10-06 22:19 GMT+04:00 Serge E. Hallyn <serge@hallyn.com>: > Quoting Andrey Wagin (avagin@gmail.com): >> Hi All, >> >> Here is a small program, which triggers a bug. Is it interested for someone? > > Yup, would > > diff --git a/fs/namespace.c b/fs/namespace.c > index ef42d9b..ddef25d 100644 > --- a/fs/namespace.c > +++ b/fs/namespace.c > @@ -3046,6 +3046,9 @@ static int mntns_install(struct nsproxy *nsproxy, void *ns) > struct mnt_namespace *mnt_ns = ns; > struct path root; > > + if (mnt_ns == nsproxy->mnt_ns) > + return 0; > + > if (!ns_capable(mnt_ns->user_ns, CAP_SYS_ADMIN) || > !ns_capable(current_user_ns(), CAP_SYS_CHROOT) || > !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) > > fix it? Actually the bug is triggered from the second umount. I think we need something like this: diff --git a/fs/namespace.c b/fs/namespace.c index 68685b2..bbcd92c 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1363,6 +1363,9 @@ static int do_umount(struct mount *mnt, int flags) return retval; } + if (mnt->mnt_parent == mnt) + return -EINVAL; + namespace_lock(); lock_mount_hash(); event++; root@ubuntu:/home/avagin# strace ./a.out ... open("/proc/self/ns/mnt", O_RDONLY) = 3 umount("/", MNT_DETACH) = 0 setns(3, 131072) = 0 umount("/", MNT_DETACH) = -1 EINVAL (Invalid argument) exit_group(0) = ? +++ exited with 0 +++ > >> root@ubuntu:/home/avagin# cat nsenter.c >> #define _GNU_SOURCE /* See feature_test_macros(7) */ >> #include <sched.h> >> #include <sys/types.h> >> #include <sys/stat.h> >> #include <fcntl.h> >> #include <unistd.h> >> #include <sys/mount.h> >> >> int main(int argc, char **argv) >> { >> int fd; >> >> fd = open("/proc/self/ns/mnt", O_RDONLY); >> if (fd < 0) >> return 1; >> umount2("/", MNT_DETACH); >> if (setns(fd, CLONE_NEWNS)) >> return 1; >> umount2("/", MNT_DETACH); >> >> return 0; >> } >> >> root@ubuntu:/home/avagin# gcc nsenter.c -o nsenter >> root@ubuntu:/home/avagin# ./nsenter >> >> >> [ 260.548301] ------------[ cut here ]------------ >> [ 260.550941] kernel BUG at /build/buildd/linux-3.13.0/fs/pnode.c:372! >> [ 260.552068] invalid opcode: 0000 [#1] SMP >> [ 260.552068] Modules linked in: xt_CHECKSUM iptable_mangle xt_tcpudp >> xt_addrtype xt_conntrack ipt_MASQUERADE iptable_nat nf_conntrack_ipv4 >> nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack bridge stp llc >> dm_thin_pool dm_persistent_data dm_bufio dm_bio_prison iptable_filter >> ip_tables x_tables crct10dif_pclmul crc32_pclmul ghash_clmulni_intel >> binfmt_misc nfsd auth_rpcgss nfs_acl aesni_intel nfs lockd aes_x86_64 >> sunrpc fscache lrw gf128mul glue_helper ablk_helper cryptd serio_raw >> ppdev parport_pc lp parport btrfs xor raid6_pq libcrc32c psmouse >> floppy >> [ 260.552068] CPU: 0 PID: 1723 Comm: nsenter Not tainted >> 3.13.0-30-generic #55-Ubuntu >> [ 260.552068] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 >> [ 260.552068] task: ffff8800376097f0 ti: ffff880074824000 task.ti: >> ffff880074824000 >> [ 260.552068] RIP: 0010:[<ffffffff811e9483>] [<ffffffff811e9483>] >> propagate_umount+0x123/0x130 >> [ 260.552068] RSP: 0018:ffff880074825e98 EFLAGS: 00010246 >> [ 260.552068] RAX: ffff88007c741140 RBX: 0000000000000002 RCX: ffff88007c741190 >> [ 260.552068] RDX: ffff88007c741190 RSI: ffff880074825ec0 RDI: ffff880074825ec0 >> [ 260.552068] RBP: ffff880074825eb0 R08: 00000000000172e0 R09: ffff88007fc172e0 >> [ 260.552068] R10: ffffffff811cc642 R11: ffffea0001d59000 R12: ffff88007c741140 >> [ 260.552068] R13: ffff88007c741140 R14: ffff88007c741140 R15: 0000000000000000 >> [ 260.552068] FS: 00007fd5c7e41740(0000) GS:ffff88007fc00000(0000) >> knlGS:0000000000000000 >> [ 260.552068] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> [ 260.552068] CR2: 00007fd5c7968050 CR3: 0000000070124000 CR4: 00000000000406f0 >> [ 260.552068] Stack: >> [ 260.552068] 0000000000000002 0000000000000002 ffff88007c631000 >> ffff880074825ed8 >> [ 260.552068] ffffffff811dcfac ffff88007c741140 0000000000000002 >> ffff88007c741160 >> [ 260.552068] ffff880074825f38 ffffffff811dd12b ffffffff811cc642 >> 0000000075640000 >> [ 260.552068] Call Trace: >> [ 260.552068] [<ffffffff811dcfac>] umount_tree+0x20c/0x260 >> [ 260.552068] [<ffffffff811dd12b>] do_umount+0x12b/0x300 >> [ 260.552068] [<ffffffff811cc642>] ? final_putname+0x22/0x50 >> [ 260.552068] [<ffffffff811cc849>] ? putname+0x29/0x40 >> [ 260.552068] [<ffffffff811dd88c>] SyS_umount+0xdc/0x100 >> [ 260.552068] [<ffffffff8172aeff>] tracesys+0xe1/0xe6 >> [ 260.552068] Code: 89 50 08 48 8b 50 08 48 89 02 49 89 45 08 e9 72 >> ff ff ff 0f 1f 44 00 00 4c 89 e6 4c 89 e7 e8 f5 f6 ff ff 48 89 c3 e9 >> 39 ff ff ff <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 66 66 66 66 90 55 >> b8 01 >> [ 260.552068] RIP [<ffffffff811e9483>] propagate_umount+0x123/0x130 >> [ 260.552068] RSP <ffff880074825e98> >> [ 260.611451] ---[ end trace 11c33d85f1d4c652 ]--- >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> Please read the FAQ at http://www.tux.org/lkml/ ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: BUG at /build/buildd/linux-3.13.0/fs/pnode.c:372! 2014-10-06 19:30 ` Andrey Wagin @ 2014-10-06 19:44 ` Serge E. Hallyn 2014-10-06 19:50 ` Andrey Wagin 0 siblings, 1 reply; 5+ messages in thread From: Serge E. Hallyn @ 2014-10-06 19:44 UTC (permalink / raw) To: Andrey Wagin; +Cc: Serge E. Hallyn, linux-fsdevel, LKML Quoting Andrey Wagin (avagin@gmail.com): > 2014-10-06 22:19 GMT+04:00 Serge E. Hallyn <serge@hallyn.com>: > > Quoting Andrey Wagin (avagin@gmail.com): > >> Hi All, > >> > >> Here is a small program, which triggers a bug. Is it interested for someone? > > > > Yup, would > > > > diff --git a/fs/namespace.c b/fs/namespace.c > > index ef42d9b..ddef25d 100644 > > --- a/fs/namespace.c > > +++ b/fs/namespace.c > > @@ -3046,6 +3046,9 @@ static int mntns_install(struct nsproxy *nsproxy, void *ns) > > struct mnt_namespace *mnt_ns = ns; > > struct path root; > > > > + if (mnt_ns == nsproxy->mnt_ns) > > + return 0; > > + > > if (!ns_capable(mnt_ns->user_ns, CAP_SYS_ADMIN) || > > !ns_capable(current_user_ns(), CAP_SYS_CHROOT) || > > !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) > > > > fix it? > > Actually the bug is triggered from the second umount. I think we need Oh, I see. > something like this: > diff --git a/fs/namespace.c b/fs/namespace.c > index 68685b2..bbcd92c 100644 > --- a/fs/namespace.c > +++ b/fs/namespace.c > @@ -1363,6 +1363,9 @@ static int do_umount(struct mount *mnt, int flags) > return retval; > } > > + if (mnt->mnt_parent == mnt) looks good (or the equivalent mnt_has_parent(mnt)). Have you tested that this prevents your test program from causing a crash? > + return -EINVAL; > + > namespace_lock(); > lock_mount_hash(); > event++; > > root@ubuntu:/home/avagin# strace ./a.out > ... > open("/proc/self/ns/mnt", O_RDONLY) = 3 > umount("/", MNT_DETACH) = 0 > setns(3, 131072) = 0 > umount("/", MNT_DETACH) = -1 EINVAL (Invalid argument) > exit_group(0) = ? > +++ exited with 0 +++ > > > > >> root@ubuntu:/home/avagin# cat nsenter.c > >> #define _GNU_SOURCE /* See feature_test_macros(7) */ > >> #include <sched.h> > >> #include <sys/types.h> > >> #include <sys/stat.h> > >> #include <fcntl.h> > >> #include <unistd.h> > >> #include <sys/mount.h> > >> > >> int main(int argc, char **argv) > >> { > >> int fd; > >> > >> fd = open("/proc/self/ns/mnt", O_RDONLY); > >> if (fd < 0) > >> return 1; > >> umount2("/", MNT_DETACH); > >> if (setns(fd, CLONE_NEWNS)) > >> return 1; > >> umount2("/", MNT_DETACH); > >> > >> return 0; > >> } > >> > >> root@ubuntu:/home/avagin# gcc nsenter.c -o nsenter > >> root@ubuntu:/home/avagin# ./nsenter > >> > >> > >> [ 260.548301] ------------[ cut here ]------------ > >> [ 260.550941] kernel BUG at /build/buildd/linux-3.13.0/fs/pnode.c:372! > >> [ 260.552068] invalid opcode: 0000 [#1] SMP > >> [ 260.552068] Modules linked in: xt_CHECKSUM iptable_mangle xt_tcpudp > >> xt_addrtype xt_conntrack ipt_MASQUERADE iptable_nat nf_conntrack_ipv4 > >> nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack bridge stp llc > >> dm_thin_pool dm_persistent_data dm_bufio dm_bio_prison iptable_filter > >> ip_tables x_tables crct10dif_pclmul crc32_pclmul ghash_clmulni_intel > >> binfmt_misc nfsd auth_rpcgss nfs_acl aesni_intel nfs lockd aes_x86_64 > >> sunrpc fscache lrw gf128mul glue_helper ablk_helper cryptd serio_raw > >> ppdev parport_pc lp parport btrfs xor raid6_pq libcrc32c psmouse > >> floppy > >> [ 260.552068] CPU: 0 PID: 1723 Comm: nsenter Not tainted > >> 3.13.0-30-generic #55-Ubuntu > >> [ 260.552068] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 > >> [ 260.552068] task: ffff8800376097f0 ti: ffff880074824000 task.ti: > >> ffff880074824000 > >> [ 260.552068] RIP: 0010:[<ffffffff811e9483>] [<ffffffff811e9483>] > >> propagate_umount+0x123/0x130 > >> [ 260.552068] RSP: 0018:ffff880074825e98 EFLAGS: 00010246 > >> [ 260.552068] RAX: ffff88007c741140 RBX: 0000000000000002 RCX: ffff88007c741190 > >> [ 260.552068] RDX: ffff88007c741190 RSI: ffff880074825ec0 RDI: ffff880074825ec0 > >> [ 260.552068] RBP: ffff880074825eb0 R08: 00000000000172e0 R09: ffff88007fc172e0 > >> [ 260.552068] R10: ffffffff811cc642 R11: ffffea0001d59000 R12: ffff88007c741140 > >> [ 260.552068] R13: ffff88007c741140 R14: ffff88007c741140 R15: 0000000000000000 > >> [ 260.552068] FS: 00007fd5c7e41740(0000) GS:ffff88007fc00000(0000) > >> knlGS:0000000000000000 > >> [ 260.552068] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > >> [ 260.552068] CR2: 00007fd5c7968050 CR3: 0000000070124000 CR4: 00000000000406f0 > >> [ 260.552068] Stack: > >> [ 260.552068] 0000000000000002 0000000000000002 ffff88007c631000 > >> ffff880074825ed8 > >> [ 260.552068] ffffffff811dcfac ffff88007c741140 0000000000000002 > >> ffff88007c741160 > >> [ 260.552068] ffff880074825f38 ffffffff811dd12b ffffffff811cc642 > >> 0000000075640000 > >> [ 260.552068] Call Trace: > >> [ 260.552068] [<ffffffff811dcfac>] umount_tree+0x20c/0x260 > >> [ 260.552068] [<ffffffff811dd12b>] do_umount+0x12b/0x300 > >> [ 260.552068] [<ffffffff811cc642>] ? final_putname+0x22/0x50 > >> [ 260.552068] [<ffffffff811cc849>] ? putname+0x29/0x40 > >> [ 260.552068] [<ffffffff811dd88c>] SyS_umount+0xdc/0x100 > >> [ 260.552068] [<ffffffff8172aeff>] tracesys+0xe1/0xe6 > >> [ 260.552068] Code: 89 50 08 48 8b 50 08 48 89 02 49 89 45 08 e9 72 > >> ff ff ff 0f 1f 44 00 00 4c 89 e6 4c 89 e7 e8 f5 f6 ff ff 48 89 c3 e9 > >> 39 ff ff ff <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 66 66 66 66 90 55 > >> b8 01 > >> [ 260.552068] RIP [<ffffffff811e9483>] propagate_umount+0x123/0x130 > >> [ 260.552068] RSP <ffff880074825e98> > >> [ 260.611451] ---[ end trace 11c33d85f1d4c652 ]--- > >> -- > >> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > >> the body of a message to majordomo@vger.kernel.org > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > >> Please read the FAQ at http://www.tux.org/lkml/ ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: BUG at /build/buildd/linux-3.13.0/fs/pnode.c:372! 2014-10-06 19:44 ` Serge E. Hallyn @ 2014-10-06 19:50 ` Andrey Wagin 0 siblings, 0 replies; 5+ messages in thread From: Andrey Wagin @ 2014-10-06 19:50 UTC (permalink / raw) To: Serge E. Hallyn; +Cc: linux-fsdevel, LKML 2014-10-06 23:44 GMT+04:00 Serge E. Hallyn <serge@hallyn.com>: > Quoting Andrey Wagin (avagin@gmail.com): >> 2014-10-06 22:19 GMT+04:00 Serge E. Hallyn <serge@hallyn.com>: >> > Quoting Andrey Wagin (avagin@gmail.com): >> >> Hi All, >> >> >> >> Here is a small program, which triggers a bug. Is it interested for someone? >> > >> > Yup, would >> > >> > diff --git a/fs/namespace.c b/fs/namespace.c >> > index ef42d9b..ddef25d 100644 >> > --- a/fs/namespace.c >> > +++ b/fs/namespace.c >> > @@ -3046,6 +3046,9 @@ static int mntns_install(struct nsproxy *nsproxy, void *ns) >> > struct mnt_namespace *mnt_ns = ns; >> > struct path root; >> > >> > + if (mnt_ns == nsproxy->mnt_ns) >> > + return 0; >> > + >> > if (!ns_capable(mnt_ns->user_ns, CAP_SYS_ADMIN) || >> > !ns_capable(current_user_ns(), CAP_SYS_CHROOT) || >> > !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) >> > >> > fix it? >> >> Actually the bug is triggered from the second umount. I think we need > > Oh, I see. > >> something like this: >> diff --git a/fs/namespace.c b/fs/namespace.c >> index 68685b2..bbcd92c 100644 >> --- a/fs/namespace.c >> +++ b/fs/namespace.c >> @@ -1363,6 +1363,9 @@ static int do_umount(struct mount *mnt, int flags) >> return retval; >> } >> >> + if (mnt->mnt_parent == mnt) > > looks good (or the equivalent mnt_has_parent(mnt)). Have you tested that > this prevents your test program from causing a crash? Yes, I have. Look the strace output below. Today here is too late for sending a proper patch. > >> + return -EINVAL; >> + >> namespace_lock(); >> lock_mount_hash(); >> event++; >> >> root@ubuntu:/home/avagin# strace ./a.out >> ... >> open("/proc/self/ns/mnt", O_RDONLY) = 3 >> umount("/", MNT_DETACH) = 0 >> setns(3, 131072) = 0 >> umount("/", MNT_DETACH) = -1 EINVAL (Invalid argument) >> exit_group(0) = ? >> +++ exited with 0 +++ >> >> > >> >> root@ubuntu:/home/avagin# cat nsenter.c >> >> #define _GNU_SOURCE /* See feature_test_macros(7) */ >> >> #include <sched.h> >> >> #include <sys/types.h> >> >> #include <sys/stat.h> >> >> #include <fcntl.h> >> >> #include <unistd.h> >> >> #include <sys/mount.h> >> >> >> >> int main(int argc, char **argv) >> >> { >> >> int fd; >> >> >> >> fd = open("/proc/self/ns/mnt", O_RDONLY); >> >> if (fd < 0) >> >> return 1; >> >> umount2("/", MNT_DETACH); >> >> if (setns(fd, CLONE_NEWNS)) >> >> return 1; >> >> umount2("/", MNT_DETACH); >> >> >> >> return 0; >> >> } >> >> >> >> root@ubuntu:/home/avagin# gcc nsenter.c -o nsenter >> >> root@ubuntu:/home/avagin# ./nsenter >> >> >> >> >> >> [ 260.548301] ------------[ cut here ]------------ >> >> [ 260.550941] kernel BUG at /build/buildd/linux-3.13.0/fs/pnode.c:372! >> >> [ 260.552068] invalid opcode: 0000 [#1] SMP >> >> [ 260.552068] Modules linked in: xt_CHECKSUM iptable_mangle xt_tcpudp >> >> xt_addrtype xt_conntrack ipt_MASQUERADE iptable_nat nf_conntrack_ipv4 >> >> nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack bridge stp llc >> >> dm_thin_pool dm_persistent_data dm_bufio dm_bio_prison iptable_filter >> >> ip_tables x_tables crct10dif_pclmul crc32_pclmul ghash_clmulni_intel >> >> binfmt_misc nfsd auth_rpcgss nfs_acl aesni_intel nfs lockd aes_x86_64 >> >> sunrpc fscache lrw gf128mul glue_helper ablk_helper cryptd serio_raw >> >> ppdev parport_pc lp parport btrfs xor raid6_pq libcrc32c psmouse >> >> floppy >> >> [ 260.552068] CPU: 0 PID: 1723 Comm: nsenter Not tainted >> >> 3.13.0-30-generic #55-Ubuntu >> >> [ 260.552068] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 >> >> [ 260.552068] task: ffff8800376097f0 ti: ffff880074824000 task.ti: >> >> ffff880074824000 >> >> [ 260.552068] RIP: 0010:[<ffffffff811e9483>] [<ffffffff811e9483>] >> >> propagate_umount+0x123/0x130 >> >> [ 260.552068] RSP: 0018:ffff880074825e98 EFLAGS: 00010246 >> >> [ 260.552068] RAX: ffff88007c741140 RBX: 0000000000000002 RCX: ffff88007c741190 >> >> [ 260.552068] RDX: ffff88007c741190 RSI: ffff880074825ec0 RDI: ffff880074825ec0 >> >> [ 260.552068] RBP: ffff880074825eb0 R08: 00000000000172e0 R09: ffff88007fc172e0 >> >> [ 260.552068] R10: ffffffff811cc642 R11: ffffea0001d59000 R12: ffff88007c741140 >> >> [ 260.552068] R13: ffff88007c741140 R14: ffff88007c741140 R15: 0000000000000000 >> >> [ 260.552068] FS: 00007fd5c7e41740(0000) GS:ffff88007fc00000(0000) >> >> knlGS:0000000000000000 >> >> [ 260.552068] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> >> [ 260.552068] CR2: 00007fd5c7968050 CR3: 0000000070124000 CR4: 00000000000406f0 >> >> [ 260.552068] Stack: >> >> [ 260.552068] 0000000000000002 0000000000000002 ffff88007c631000 >> >> ffff880074825ed8 >> >> [ 260.552068] ffffffff811dcfac ffff88007c741140 0000000000000002 >> >> ffff88007c741160 >> >> [ 260.552068] ffff880074825f38 ffffffff811dd12b ffffffff811cc642 >> >> 0000000075640000 >> >> [ 260.552068] Call Trace: >> >> [ 260.552068] [<ffffffff811dcfac>] umount_tree+0x20c/0x260 >> >> [ 260.552068] [<ffffffff811dd12b>] do_umount+0x12b/0x300 >> >> [ 260.552068] [<ffffffff811cc642>] ? final_putname+0x22/0x50 >> >> [ 260.552068] [<ffffffff811cc849>] ? putname+0x29/0x40 >> >> [ 260.552068] [<ffffffff811dd88c>] SyS_umount+0xdc/0x100 >> >> [ 260.552068] [<ffffffff8172aeff>] tracesys+0xe1/0xe6 >> >> [ 260.552068] Code: 89 50 08 48 8b 50 08 48 89 02 49 89 45 08 e9 72 >> >> ff ff ff 0f 1f 44 00 00 4c 89 e6 4c 89 e7 e8 f5 f6 ff ff 48 89 c3 e9 >> >> 39 ff ff ff <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 66 66 66 66 90 55 >> >> b8 01 >> >> [ 260.552068] RIP [<ffffffff811e9483>] propagate_umount+0x123/0x130 >> >> [ 260.552068] RSP <ffff880074825e98> >> >> [ 260.611451] ---[ end trace 11c33d85f1d4c652 ]--- >> >> -- >> >> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >> >> the body of a message to majordomo@vger.kernel.org >> >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >> Please read the FAQ at http://www.tux.org/lkml/ ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2014-10-06 19:50 UTC | newest] Thread overview: 5+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2014-10-06 13:29 BUG at /build/buildd/linux-3.13.0/fs/pnode.c:372! Andrey Wagin 2014-10-06 18:19 ` Serge E. Hallyn 2014-10-06 19:30 ` Andrey Wagin 2014-10-06 19:44 ` Serge E. Hallyn 2014-10-06 19:50 ` Andrey Wagin
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