* [stable bug] NFSd NULL pointer trigger kernel panic [not found] <52959F5D.4000200@huawei.com> @ 2013-11-27 7:54 ` Weng Meiling 2013-11-27 8:07 ` Stanislav Kinsbursky 0 siblings, 1 reply; 4+ messages in thread From: Weng Meiling @ 2013-11-27 7:54 UTC (permalink / raw) To: stable, linux-nfs, containers, Stanislav Kinsbursky; +Cc: Li Zefan, Huang Qiang Hi guys, When I try to test NFS in different network namespace with stable-3.4, I trigger a kernel panic. When NFSd was started in one non init_net network namespace, and stopped in another one. This will trigger kernel panic, because RPCBIND client is stored per net, and will be NULL on NFSd shutdown. The detail steps are: #ip netns add test #ip netns exec test service nfsserver start #service nfsserver stop The main call trace: [ 293.358078] BUG: unable to handle kernel NULL pointer dereference at 0000000000000060 [ 293.358089] IP: [<ffffffffa0446150>] call_start+0x10/0x30 [sunrpc] [ 293.358215] Pid: 5323, comm: nfsd Not tainted 3.4.69-default-stable+ [ 293.358321] Call Trace: [ 293.358336] [<ffffffffa044f401>] __rpc_execute+0x91/0x160 [sunrpc] [ 293.358351] [<ffffffffa044f541>] rpc_execute+0x71/0x80 [sunrpc] [ 293.358362] [<ffffffffa04479a9>] rpc_run_task+0x89/0xa0 [sunrpc] [ 293.358374] [<ffffffffa0447abd>] rpc_call_sync+0x3d/0x70 [sunrpc] [ 293.358390] [<ffffffffa0457bc6>] rpcb_register+0xa6/0xd0 [sunrpc] [ 293.358406] [<ffffffffa0452345>] svc_unregister+0x95/0xf0 [sunrpc] [ 293.358418] [<ffffffffa04ab8a0>] ? nfsd_last_thread+0x50/0x50 [nfsd] [ 293.358433] [<ffffffffa04523b1>] svc_rpcb_cleanup+0x11/0x20 [sunrpc] [ 293.358442] [<ffffffffa04ab877>] nfsd_last_thread+0x27/0x50 [nfsd] [ 293.358457] [<ffffffffa0452280>] svc_shutdown_net+0x30/0x40 [sunrpc] [ 293.358466] [<ffffffffa04ab9ed>] nfsd+0x14d/0x1a0 [nfsd] [ 293.358475] [<ffffffffa04ab8a0>] ? nfsd_last_thread+0x50/0x50 [nfsd] [ 293.358487] [<ffffffff8106459e>] kthread+0x9e/0xb0 [ 293.358496] [<ffffffff81465014>] kernel_thread_helper+0x4/0x10 [ 293.358503] [<ffffffff81064500>] ? kthread_freezable_should_stop+0x70/0x70 [ 293.358509] [<ffffffff81465010>] ? gs_change+0x13/0x13 Walk through the code, this problem also exists in stable-3.5 to stable-3.7. Stanislav Kinsbursky had committed a fixed patch for 3.8: commit f7fb86c6e639360ad9c253cec534819ef928a674 (nfsd: use "init_net" for portmapper). This patch is suitable for stable-3.4, but it causes another bug, When starting NFSd in a non init_net network namespace will trigger kernel panic. Because RPCBIND client will be NULL when register RPC service with the local portmapper in svc_addsock(). This new bug also exists in 3.8, but disappears after patch commit 11f779421a39b86da8a523d97e5fd3477878d44f ("containerize NFSd filesystem") in 3.9. The detail steps are: #ip netns add test #ip netns exec test service nfsserver start The main call trace: [ 136.877527] BUG: unable to handle kernel NULL pointer dereference at 0000000000000060 [ 136.877538] IP: [<ffffffffa0451150>] call_start+0x10/0x30 [sunrpc] [ 136.877664] Pid: 4854, comm: rpc.nfsd Not tainted 3.4.69-default-stable-nfs-test+ [ 136.877769] Call Trace: [ 136.877785] [<ffffffffa045a401>] __rpc_execute+0x91/0x160 [sunrpc] [ 136.877799] [<ffffffffa045a541>] rpc_execute+0x71/0x80 [sunrpc] [ 136.877811] [<ffffffffa04529a9>] rpc_run_task+0x89/0xa0 [sunrpc] [ 136.877822] [<ffffffffa0452abd>] rpc_call_sync+0x3d/0x70 [sunrpc] [ 136.877839] [<ffffffffa0462bc6>] rpcb_register+0xa6/0xd0 [sunrpc] [ 136.877854] [<ffffffffa045ca9e>] __svc_register+0x1ae/0x1c0 [sunrpc] [ 136.877870] [<ffffffffa045cb3f>] svc_register+0x8f/0xc0 [sunrpc] [ 136.877882] [<ffffffff8114d855>] ? kmem_cache_alloc_trace+0xc5/0x1e0 [ 136.877897] [<ffffffffa045ec38>] svc_setup_socket+0x1a8/0x2c0 [sunrpc] [ 136.877907] [<ffffffff81009546>] ? read_tsc+0x16/0x40 [ 136.877922] [<ffffffffa045f9b8>] svc_addsock+0x118/0x1c0 [sunrpc] [ 136.877930] [<ffffffff8108f225>] ? do_gettimeofday+0x15/0x50 [ 136.877941] [<ffffffffa04aa69c>] ? nfsd_create_serv+0xdc/0x150 [nfsd] [ 136.877951] [<ffffffffa04abdce>] __write_ports+0x1fe/0x230 [nfsd] [ 136.877961] [<ffffffffa04abe37>] write_ports+0x37/0x60 [nfsd] [ 136.877970] [<ffffffffa04abe00>] ? __write_ports+0x230/0x230 [nfsd] [ 136.877979] [<ffffffffa04aadd2>] nfsctl_transaction_write+0x72/0x90 [nfsd] [ 136.877987] [<ffffffff8115b4ab>] vfs_write+0xcb/0x130 [ 136.877992] [<ffffffff8115b600>] sys_write+0x50/0x90 [ 136.878000] [<ffffffff81463cb9>] system_call_fastpath+0x16/0x1b Here is a way to resolve the problem: Maybe we can backport the following patches from 3.8 to cleanup init_net reference: --- Stanislav Kinsbursky (7): nfsd: use "init_net" for portmapper commit f7fb86c6e639360ad9c253cec534819ef928a674 nfsd: pass net to nfsd_init_socks() commit db6e182c17cb1a7069f7f8924721ce58ac05d9a3 nfsd: pass net to nfsd_startup() and nfsd_shutdown() commit db42d1a76a8dfcaba7a2dc9c591fa4e231db22b3 nfsd: pass net to nfsd_create_serv() commit 6777436b0f072fb20a025a73e9b67a35ad8a5451 nfsd: pass net to nfsd_svc() commit d41a9417cd89a69f58a26935034b4264a2d882d6 nfsd: pass net to nfsd_set_nrthreads() commit 3938a0d5eb5effcc89c6909741403f4e6a37252d nfsd: pass net to __write_ports() and down commit 081603520b25f7b35ef63a363376a17c36ef74ed fs/nfsd/nfsctl.c | 27 +++++++++++++++------------ fs/nfsd/nfsd.h | 6 +++--- fs/nfsd/nfssvc.c | 35 ++++++++++++++--------------------- 3 files changed, 32 insertions(+), 36 deletions(-) Stanislav Kinsbursky: nfsd: pass proper net to nfsd_destroy() from NFSd kthreads commit 88c47666171989ed4c5b1a5687df09511e8c5e35 fs/nfsd/nfssvc.c | 4 +++- 1 files changed, 3 insertions(+), 1 deletions(-) and then just a simple patch which uses the current->nsproxy->net_ns to repalce the init_net to make NFSd keep using a consistent network namespace all the time can resolve the problem. Maybe this is not optimal, what do you think about this problem? The related patches' links: http://linux-kernel.2935.n7.nabble.com/PATCH-0-7-nfsd-cleanup-quot-init-net-quot-references-td567366.html https://lkml.org/lkml/2012/12/6/161 ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [stable bug] NFSd NULL pointer trigger kernel panic 2013-11-27 7:54 ` [stable bug] NFSd NULL pointer trigger kernel panic Weng Meiling @ 2013-11-27 8:07 ` Stanislav Kinsbursky 2013-12-02 16:35 ` bfields 0 siblings, 1 reply; 4+ messages in thread From: Stanislav Kinsbursky @ 2013-11-27 8:07 UTC (permalink / raw) To: Weng Meiling, bfields@fieldses.org, linux-nfs, containers Cc: Li Zefan, Huang Qiang 27.11.2013 11:54, Weng Meiling пишет: > > Hi guys, > > When I try to test NFS in different network namespace with stable-3.4, > I trigger a kernel panic. When NFSd was started in one non init_net network > namespace, and stopped in another one. This will trigger kernel panic, because > RPCBIND client is stored per net, and will be NULL on NFSd shutdown. > > The detail steps are: > > #ip netns add test > #ip netns exec test service nfsserver start > #service nfsserver stop > > The main call trace: > > [ 293.358078] BUG: unable to handle kernel NULL pointer dereference at 0000000000000060 > [ 293.358089] IP: [<ffffffffa0446150>] call_start+0x10/0x30 [sunrpc] > > [ 293.358215] Pid: 5323, comm: nfsd Not tainted 3.4.69-default-stable+ > > [ 293.358321] Call Trace: > [ 293.358336] [<ffffffffa044f401>] __rpc_execute+0x91/0x160 [sunrpc] > [ 293.358351] [<ffffffffa044f541>] rpc_execute+0x71/0x80 [sunrpc] > [ 293.358362] [<ffffffffa04479a9>] rpc_run_task+0x89/0xa0 [sunrpc] > [ 293.358374] [<ffffffffa0447abd>] rpc_call_sync+0x3d/0x70 [sunrpc] > [ 293.358390] [<ffffffffa0457bc6>] rpcb_register+0xa6/0xd0 [sunrpc] > [ 293.358406] [<ffffffffa0452345>] svc_unregister+0x95/0xf0 [sunrpc] > [ 293.358418] [<ffffffffa04ab8a0>] ? nfsd_last_thread+0x50/0x50 [nfsd] > [ 293.358433] [<ffffffffa04523b1>] svc_rpcb_cleanup+0x11/0x20 [sunrpc] > [ 293.358442] [<ffffffffa04ab877>] nfsd_last_thread+0x27/0x50 [nfsd] > [ 293.358457] [<ffffffffa0452280>] svc_shutdown_net+0x30/0x40 [sunrpc] > [ 293.358466] [<ffffffffa04ab9ed>] nfsd+0x14d/0x1a0 [nfsd] > [ 293.358475] [<ffffffffa04ab8a0>] ? nfsd_last_thread+0x50/0x50 [nfsd] > [ 293.358487] [<ffffffff8106459e>] kthread+0x9e/0xb0 > [ 293.358496] [<ffffffff81465014>] kernel_thread_helper+0x4/0x10 > [ 293.358503] [<ffffffff81064500>] ? kthread_freezable_should_stop+0x70/0x70 > [ 293.358509] [<ffffffff81465010>] ? gs_change+0x13/0x13 > > Walk through the code, this problem also exists in stable-3.5 to stable-3.7. > Stanislav Kinsbursky had committed a fixed patch for 3.8: > commit f7fb86c6e639360ad9c253cec534819ef928a674 (nfsd: use "init_net" for portmapper). > This patch is suitable for stable-3.4, but it causes another bug, When starting NFSd > in a non init_net network namespace will trigger kernel panic. Because RPCBIND client > will be NULL when register RPC service with the local portmapper in svc_addsock(). This > new bug also exists in 3.8, but disappears after patch commit 11f779421a39b86da8a523d97e5fd3477878d44f > ("containerize NFSd filesystem") in 3.9. > > The detail steps are: > > #ip netns add test > #ip netns exec test service nfsserver start > > The main call trace: > > [ 136.877527] BUG: unable to handle kernel NULL pointer dereference at 0000000000000060 > [ 136.877538] IP: [<ffffffffa0451150>] call_start+0x10/0x30 [sunrpc] > > [ 136.877664] Pid: 4854, comm: rpc.nfsd Not tainted 3.4.69-default-stable-nfs-test+ > > [ 136.877769] Call Trace: > [ 136.877785] [<ffffffffa045a401>] __rpc_execute+0x91/0x160 [sunrpc] > [ 136.877799] [<ffffffffa045a541>] rpc_execute+0x71/0x80 [sunrpc] > [ 136.877811] [<ffffffffa04529a9>] rpc_run_task+0x89/0xa0 [sunrpc] > [ 136.877822] [<ffffffffa0452abd>] rpc_call_sync+0x3d/0x70 [sunrpc] > [ 136.877839] [<ffffffffa0462bc6>] rpcb_register+0xa6/0xd0 [sunrpc] > [ 136.877854] [<ffffffffa045ca9e>] __svc_register+0x1ae/0x1c0 [sunrpc] > [ 136.877870] [<ffffffffa045cb3f>] svc_register+0x8f/0xc0 [sunrpc] > [ 136.877882] [<ffffffff8114d855>] ? kmem_cache_alloc_trace+0xc5/0x1e0 > [ 136.877897] [<ffffffffa045ec38>] svc_setup_socket+0x1a8/0x2c0 [sunrpc] > [ 136.877907] [<ffffffff81009546>] ? read_tsc+0x16/0x40 > [ 136.877922] [<ffffffffa045f9b8>] svc_addsock+0x118/0x1c0 [sunrpc] > [ 136.877930] [<ffffffff8108f225>] ? do_gettimeofday+0x15/0x50 > [ 136.877941] [<ffffffffa04aa69c>] ? nfsd_create_serv+0xdc/0x150 [nfsd] > [ 136.877951] [<ffffffffa04abdce>] __write_ports+0x1fe/0x230 [nfsd] > [ 136.877961] [<ffffffffa04abe37>] write_ports+0x37/0x60 [nfsd] > [ 136.877970] [<ffffffffa04abe00>] ? __write_ports+0x230/0x230 [nfsd] > [ 136.877979] [<ffffffffa04aadd2>] nfsctl_transaction_write+0x72/0x90 [nfsd] > [ 136.877987] [<ffffffff8115b4ab>] vfs_write+0xcb/0x130 > [ 136.877992] [<ffffffff8115b600>] sys_write+0x50/0x90 > [ 136.878000] [<ffffffff81463cb9>] system_call_fastpath+0x16/0x1b > > > Here is a way to resolve the problem: > Maybe we can backport the following patches from 3.8 to cleanup init_net reference: > > --- > > Stanislav Kinsbursky (7): > nfsd: use "init_net" for portmapper commit f7fb86c6e639360ad9c253cec534819ef928a674 > nfsd: pass net to nfsd_init_socks() commit db6e182c17cb1a7069f7f8924721ce58ac05d9a3 > nfsd: pass net to nfsd_startup() and nfsd_shutdown() commit db42d1a76a8dfcaba7a2dc9c591fa4e231db22b3 > nfsd: pass net to nfsd_create_serv() commit 6777436b0f072fb20a025a73e9b67a35ad8a5451 > nfsd: pass net to nfsd_svc() commit d41a9417cd89a69f58a26935034b4264a2d882d6 > nfsd: pass net to nfsd_set_nrthreads() commit 3938a0d5eb5effcc89c6909741403f4e6a37252d > nfsd: pass net to __write_ports() and down commit 081603520b25f7b35ef63a363376a17c36ef74ed > > > fs/nfsd/nfsctl.c | 27 +++++++++++++++------------ > fs/nfsd/nfsd.h | 6 +++--- > fs/nfsd/nfssvc.c | 35 ++++++++++++++--------------------- > 3 files changed, 32 insertions(+), 36 deletions(-) > > Stanislav Kinsbursky: > nfsd: pass proper net to nfsd_destroy() from NFSd kthreads commit 88c47666171989ed4c5b1a5687df09511e8c5e35 > > fs/nfsd/nfssvc.c | 4 +++- > 1 files changed, 3 insertions(+), 1 deletions(-) > > and then just a simple patch which uses the current->nsproxy->net_ns to repalce the > init_net to make NFSd keep using a consistent network namespace all the time can > resolve the problem. Maybe this is not optimal, what do you think about this problem? > Great investigation! Thanks. I think it's up to Bruce (cc'd) what is better: backport or simple fix, which just forbids NFSd start in non-init network namespace for kernels, prior to 3.9. > The related patches' links: > http://linux-kernel.2935.n7.nabble.com/PATCH-0-7-nfsd-cleanup-quot-init-net-quot-references-td567366.html > https://lkml.org/lkml/2012/12/6/161 > > > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Best regards, Stanislav Kinsbursky ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [stable bug] NFSd NULL pointer trigger kernel panic 2013-11-27 8:07 ` Stanislav Kinsbursky @ 2013-12-02 16:35 ` bfields 2013-12-03 1:24 ` Weng Meiling 0 siblings, 1 reply; 4+ messages in thread From: bfields @ 2013-12-02 16:35 UTC (permalink / raw) To: Stanislav Kinsbursky Cc: Weng Meiling, linux-nfs, containers, Li Zefan, Huang Qiang On Wed, Nov 27, 2013 at 12:07:51PM +0400, Stanislav Kinsbursky wrote: > 27.11.2013 11:54, Weng Meiling пишет: > > > >Hi guys, > > > >When I try to test NFS in different network namespace with stable-3.4, > >I trigger a kernel panic. When NFSd was started in one non init_net network > >namespace, and stopped in another one. This will trigger kernel panic, because > >RPCBIND client is stored per net, and will be NULL on NFSd shutdown. > > > >The detail steps are: > > > >#ip netns add test > >#ip netns exec test service nfsserver start > >#service nfsserver stop > > > >The main call trace: > > > >[ 293.358078] BUG: unable to handle kernel NULL pointer dereference at 0000000000000060 > >[ 293.358089] IP: [<ffffffffa0446150>] call_start+0x10/0x30 [sunrpc] > > > >[ 293.358215] Pid: 5323, comm: nfsd Not tainted 3.4.69-default-stable+ > > > >[ 293.358321] Call Trace: > >[ 293.358336] [<ffffffffa044f401>] __rpc_execute+0x91/0x160 [sunrpc] > >[ 293.358351] [<ffffffffa044f541>] rpc_execute+0x71/0x80 [sunrpc] > >[ 293.358362] [<ffffffffa04479a9>] rpc_run_task+0x89/0xa0 [sunrpc] > >[ 293.358374] [<ffffffffa0447abd>] rpc_call_sync+0x3d/0x70 [sunrpc] > >[ 293.358390] [<ffffffffa0457bc6>] rpcb_register+0xa6/0xd0 [sunrpc] > >[ 293.358406] [<ffffffffa0452345>] svc_unregister+0x95/0xf0 [sunrpc] > >[ 293.358418] [<ffffffffa04ab8a0>] ? nfsd_last_thread+0x50/0x50 [nfsd] > >[ 293.358433] [<ffffffffa04523b1>] svc_rpcb_cleanup+0x11/0x20 [sunrpc] > >[ 293.358442] [<ffffffffa04ab877>] nfsd_last_thread+0x27/0x50 [nfsd] > >[ 293.358457] [<ffffffffa0452280>] svc_shutdown_net+0x30/0x40 [sunrpc] > >[ 293.358466] [<ffffffffa04ab9ed>] nfsd+0x14d/0x1a0 [nfsd] > >[ 293.358475] [<ffffffffa04ab8a0>] ? nfsd_last_thread+0x50/0x50 [nfsd] > >[ 293.358487] [<ffffffff8106459e>] kthread+0x9e/0xb0 > >[ 293.358496] [<ffffffff81465014>] kernel_thread_helper+0x4/0x10 > >[ 293.358503] [<ffffffff81064500>] ? kthread_freezable_should_stop+0x70/0x70 > >[ 293.358509] [<ffffffff81465010>] ? gs_change+0x13/0x13 > > > >Walk through the code, this problem also exists in stable-3.5 to stable-3.7. > >Stanislav Kinsbursky had committed a fixed patch for 3.8: > >commit f7fb86c6e639360ad9c253cec534819ef928a674 (nfsd: use "init_net" for portmapper). > >This patch is suitable for stable-3.4, but it causes another bug, When starting NFSd > >in a non init_net network namespace will trigger kernel panic. Because RPCBIND client > >will be NULL when register RPC service with the local portmapper in svc_addsock(). This > >new bug also exists in 3.8, but disappears after patch commit 11f779421a39b86da8a523d97e5fd3477878d44f > >("containerize NFSd filesystem") in 3.9. > > > >The detail steps are: > > > >#ip netns add test > >#ip netns exec test service nfsserver start > > > >The main call trace: > > > >[ 136.877527] BUG: unable to handle kernel NULL pointer dereference at 0000000000000060 > >[ 136.877538] IP: [<ffffffffa0451150>] call_start+0x10/0x30 [sunrpc] > > > >[ 136.877664] Pid: 4854, comm: rpc.nfsd Not tainted 3.4.69-default-stable-nfs-test+ > > > >[ 136.877769] Call Trace: > >[ 136.877785] [<ffffffffa045a401>] __rpc_execute+0x91/0x160 [sunrpc] > >[ 136.877799] [<ffffffffa045a541>] rpc_execute+0x71/0x80 [sunrpc] > >[ 136.877811] [<ffffffffa04529a9>] rpc_run_task+0x89/0xa0 [sunrpc] > >[ 136.877822] [<ffffffffa0452abd>] rpc_call_sync+0x3d/0x70 [sunrpc] > >[ 136.877839] [<ffffffffa0462bc6>] rpcb_register+0xa6/0xd0 [sunrpc] > >[ 136.877854] [<ffffffffa045ca9e>] __svc_register+0x1ae/0x1c0 [sunrpc] > >[ 136.877870] [<ffffffffa045cb3f>] svc_register+0x8f/0xc0 [sunrpc] > >[ 136.877882] [<ffffffff8114d855>] ? kmem_cache_alloc_trace+0xc5/0x1e0 > >[ 136.877897] [<ffffffffa045ec38>] svc_setup_socket+0x1a8/0x2c0 [sunrpc] > >[ 136.877907] [<ffffffff81009546>] ? read_tsc+0x16/0x40 > >[ 136.877922] [<ffffffffa045f9b8>] svc_addsock+0x118/0x1c0 [sunrpc] > >[ 136.877930] [<ffffffff8108f225>] ? do_gettimeofday+0x15/0x50 > >[ 136.877941] [<ffffffffa04aa69c>] ? nfsd_create_serv+0xdc/0x150 [nfsd] > >[ 136.877951] [<ffffffffa04abdce>] __write_ports+0x1fe/0x230 [nfsd] > >[ 136.877961] [<ffffffffa04abe37>] write_ports+0x37/0x60 [nfsd] > >[ 136.877970] [<ffffffffa04abe00>] ? __write_ports+0x230/0x230 [nfsd] > >[ 136.877979] [<ffffffffa04aadd2>] nfsctl_transaction_write+0x72/0x90 [nfsd] > >[ 136.877987] [<ffffffff8115b4ab>] vfs_write+0xcb/0x130 > >[ 136.877992] [<ffffffff8115b600>] sys_write+0x50/0x90 > >[ 136.878000] [<ffffffff81463cb9>] system_call_fastpath+0x16/0x1b > > > > > >Here is a way to resolve the problem: > >Maybe we can backport the following patches from 3.8 to cleanup init_net reference: > > > >--- > > > >Stanislav Kinsbursky (7): > > nfsd: use "init_net" for portmapper commit f7fb86c6e639360ad9c253cec534819ef928a674 > > nfsd: pass net to nfsd_init_socks() commit db6e182c17cb1a7069f7f8924721ce58ac05d9a3 > > nfsd: pass net to nfsd_startup() and nfsd_shutdown() commit db42d1a76a8dfcaba7a2dc9c591fa4e231db22b3 > > nfsd: pass net to nfsd_create_serv() commit 6777436b0f072fb20a025a73e9b67a35ad8a5451 > > nfsd: pass net to nfsd_svc() commit d41a9417cd89a69f58a26935034b4264a2d882d6 > > nfsd: pass net to nfsd_set_nrthreads() commit 3938a0d5eb5effcc89c6909741403f4e6a37252d > > nfsd: pass net to __write_ports() and down commit 081603520b25f7b35ef63a363376a17c36ef74ed > > > > > > fs/nfsd/nfsctl.c | 27 +++++++++++++++------------ > > fs/nfsd/nfsd.h | 6 +++--- > > fs/nfsd/nfssvc.c | 35 ++++++++++++++--------------------- > > 3 files changed, 32 insertions(+), 36 deletions(-) > > > >Stanislav Kinsbursky: > > nfsd: pass proper net to nfsd_destroy() from NFSd kthreads commit 88c47666171989ed4c5b1a5687df09511e8c5e35 > > > > fs/nfsd/nfssvc.c | 4 +++- > > 1 files changed, 3 insertions(+), 1 deletions(-) > > > >and then just a simple patch which uses the current->nsproxy->net_ns to repalce the > >init_net to make NFSd keep using a consistent network namespace all the time can > >resolve the problem. Maybe this is not optimal, what do you think about this problem? > > > > Great investigation! Thanks. > I think it's up to Bruce (cc'd) what is better: backport or simple fix, which just forbids > NFSd start in non-init network namespace for kernels, prior to 3.9. It seems rude to turn off a feature in a stable series, so backports are probably better if we need to fix this. But somebody would need to test the backports. Weng Meiling, if you want this fixed on a stable branch: - confirm that those patches fix the problem. - send the resulting patches to stable@vger.kernel.org with cc:'s to at least Stanislav and me and linux-nfs@vger.kernel.org and I can ack them. --b. ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [stable bug] NFSd NULL pointer trigger kernel panic 2013-12-02 16:35 ` bfields @ 2013-12-03 1:24 ` Weng Meiling 0 siblings, 0 replies; 4+ messages in thread From: Weng Meiling @ 2013-12-03 1:24 UTC (permalink / raw) To: bfields@fieldses.org, Stanislav Kinsbursky Cc: linux-nfs, containers, Li Zefan, Huang Qiang On 2013/12/3 0:35, bfields@fieldses.org wrote: > On Wed, Nov 27, 2013 at 12:07:51PM +0400, Stanislav Kinsbursky wrote: >> 27.11.2013 11:54, Weng Meiling пишет: >>> >>> Hi guys, >>> >>> When I try to test NFS in different network namespace with stable-3.4, >>> I trigger a kernel panic. When NFSd was started in one non init_net network >>> namespace, and stopped in another one. This will trigger kernel panic, because >>> RPCBIND client is stored per net, and will be NULL on NFSd shutdown. >>> >>> The detail steps are: >>> >>> #ip netns add test >>> #ip netns exec test service nfsserver start >>> #service nfsserver stop >>> >>> The main call trace: >>> >>> [ 293.358078] BUG: unable to handle kernel NULL pointer dereference at 0000000000000060 >>> [ 293.358089] IP: [<ffffffffa0446150>] call_start+0x10/0x30 [sunrpc] >>> >>> [ 293.358215] Pid: 5323, comm: nfsd Not tainted 3.4.69-default-stable+ >>> >>> [ 293.358321] Call Trace: >>> [ 293.358336] [<ffffffffa044f401>] __rpc_execute+0x91/0x160 [sunrpc] >>> [ 293.358351] [<ffffffffa044f541>] rpc_execute+0x71/0x80 [sunrpc] >>> [ 293.358362] [<ffffffffa04479a9>] rpc_run_task+0x89/0xa0 [sunrpc] >>> [ 293.358374] [<ffffffffa0447abd>] rpc_call_sync+0x3d/0x70 [sunrpc] >>> [ 293.358390] [<ffffffffa0457bc6>] rpcb_register+0xa6/0xd0 [sunrpc] >>> [ 293.358406] [<ffffffffa0452345>] svc_unregister+0x95/0xf0 [sunrpc] >>> [ 293.358418] [<ffffffffa04ab8a0>] ? nfsd_last_thread+0x50/0x50 [nfsd] >>> [ 293.358433] [<ffffffffa04523b1>] svc_rpcb_cleanup+0x11/0x20 [sunrpc] >>> [ 293.358442] [<ffffffffa04ab877>] nfsd_last_thread+0x27/0x50 [nfsd] >>> [ 293.358457] [<ffffffffa0452280>] svc_shutdown_net+0x30/0x40 [sunrpc] >>> [ 293.358466] [<ffffffffa04ab9ed>] nfsd+0x14d/0x1a0 [nfsd] >>> [ 293.358475] [<ffffffffa04ab8a0>] ? nfsd_last_thread+0x50/0x50 [nfsd] >>> [ 293.358487] [<ffffffff8106459e>] kthread+0x9e/0xb0 >>> [ 293.358496] [<ffffffff81465014>] kernel_thread_helper+0x4/0x10 >>> [ 293.358503] [<ffffffff81064500>] ? kthread_freezable_should_stop+0x70/0x70 >>> [ 293.358509] [<ffffffff81465010>] ? gs_change+0x13/0x13 >>> >>> Walk through the code, this problem also exists in stable-3.5 to stable-3.7. >>> Stanislav Kinsbursky had committed a fixed patch for 3.8: >>> commit f7fb86c6e639360ad9c253cec534819ef928a674 (nfsd: use "init_net" for portmapper). >>> This patch is suitable for stable-3.4, but it causes another bug, When starting NFSd >>> in a non init_net network namespace will trigger kernel panic. Because RPCBIND client >>> will be NULL when register RPC service with the local portmapper in svc_addsock(). This >>> new bug also exists in 3.8, but disappears after patch commit 11f779421a39b86da8a523d97e5fd3477878d44f >>> ("containerize NFSd filesystem") in 3.9. >>> >>> The detail steps are: >>> >>> #ip netns add test >>> #ip netns exec test service nfsserver start >>> >>> The main call trace: >>> >>> [ 136.877527] BUG: unable to handle kernel NULL pointer dereference at 0000000000000060 >>> [ 136.877538] IP: [<ffffffffa0451150>] call_start+0x10/0x30 [sunrpc] >>> >>> [ 136.877664] Pid: 4854, comm: rpc.nfsd Not tainted 3.4.69-default-stable-nfs-test+ >>> >>> [ 136.877769] Call Trace: >>> [ 136.877785] [<ffffffffa045a401>] __rpc_execute+0x91/0x160 [sunrpc] >>> [ 136.877799] [<ffffffffa045a541>] rpc_execute+0x71/0x80 [sunrpc] >>> [ 136.877811] [<ffffffffa04529a9>] rpc_run_task+0x89/0xa0 [sunrpc] >>> [ 136.877822] [<ffffffffa0452abd>] rpc_call_sync+0x3d/0x70 [sunrpc] >>> [ 136.877839] [<ffffffffa0462bc6>] rpcb_register+0xa6/0xd0 [sunrpc] >>> [ 136.877854] [<ffffffffa045ca9e>] __svc_register+0x1ae/0x1c0 [sunrpc] >>> [ 136.877870] [<ffffffffa045cb3f>] svc_register+0x8f/0xc0 [sunrpc] >>> [ 136.877882] [<ffffffff8114d855>] ? kmem_cache_alloc_trace+0xc5/0x1e0 >>> [ 136.877897] [<ffffffffa045ec38>] svc_setup_socket+0x1a8/0x2c0 [sunrpc] >>> [ 136.877907] [<ffffffff81009546>] ? read_tsc+0x16/0x40 >>> [ 136.877922] [<ffffffffa045f9b8>] svc_addsock+0x118/0x1c0 [sunrpc] >>> [ 136.877930] [<ffffffff8108f225>] ? do_gettimeofday+0x15/0x50 >>> [ 136.877941] [<ffffffffa04aa69c>] ? nfsd_create_serv+0xdc/0x150 [nfsd] >>> [ 136.877951] [<ffffffffa04abdce>] __write_ports+0x1fe/0x230 [nfsd] >>> [ 136.877961] [<ffffffffa04abe37>] write_ports+0x37/0x60 [nfsd] >>> [ 136.877970] [<ffffffffa04abe00>] ? __write_ports+0x230/0x230 [nfsd] >>> [ 136.877979] [<ffffffffa04aadd2>] nfsctl_transaction_write+0x72/0x90 [nfsd] >>> [ 136.877987] [<ffffffff8115b4ab>] vfs_write+0xcb/0x130 >>> [ 136.877992] [<ffffffff8115b600>] sys_write+0x50/0x90 >>> [ 136.878000] [<ffffffff81463cb9>] system_call_fastpath+0x16/0x1b >>> >>> >>> Here is a way to resolve the problem: >>> Maybe we can backport the following patches from 3.8 to cleanup init_net reference: >>> >>> --- >>> >>> Stanislav Kinsbursky (7): >>> nfsd: use "init_net" for portmapper commit f7fb86c6e639360ad9c253cec534819ef928a674 >>> nfsd: pass net to nfsd_init_socks() commit db6e182c17cb1a7069f7f8924721ce58ac05d9a3 >>> nfsd: pass net to nfsd_startup() and nfsd_shutdown() commit db42d1a76a8dfcaba7a2dc9c591fa4e231db22b3 >>> nfsd: pass net to nfsd_create_serv() commit 6777436b0f072fb20a025a73e9b67a35ad8a5451 >>> nfsd: pass net to nfsd_svc() commit d41a9417cd89a69f58a26935034b4264a2d882d6 >>> nfsd: pass net to nfsd_set_nrthreads() commit 3938a0d5eb5effcc89c6909741403f4e6a37252d >>> nfsd: pass net to __write_ports() and down commit 081603520b25f7b35ef63a363376a17c36ef74ed >>> >>> >>> fs/nfsd/nfsctl.c | 27 +++++++++++++++------------ >>> fs/nfsd/nfsd.h | 6 +++--- >>> fs/nfsd/nfssvc.c | 35 ++++++++++++++--------------------- >>> 3 files changed, 32 insertions(+), 36 deletions(-) >>> >>> Stanislav Kinsbursky: >>> nfsd: pass proper net to nfsd_destroy() from NFSd kthreads commit 88c47666171989ed4c5b1a5687df09511e8c5e35 >>> >>> fs/nfsd/nfssvc.c | 4 +++- >>> 1 files changed, 3 insertions(+), 1 deletions(-) >>> >>> and then just a simple patch which uses the current->nsproxy->net_ns to repalce the >>> init_net to make NFSd keep using a consistent network namespace all the time can >>> resolve the problem. Maybe this is not optimal, what do you think about this problem? >>> >> >> Great investigation! Thanks. >> I think it's up to Bruce (cc'd) what is better: backport or simple fix, which just forbids >> NFSd start in non-init network namespace for kernels, prior to 3.9. > > It seems rude to turn off a feature in a stable series, so backports are > probably better if we need to fix this. But somebody would need to test > the backports. > > Weng Meiling, if you want this fixed on a stable branch: > - confirm that those patches fix the problem. > - send the resulting patches to stable@vger.kernel.org with > cc:'s to at least Stanislav and me and > linux-nfs@vger.kernel.org > > and I can ack them. > > --b. > > . > OK, I'll send these patches as soon as possible. ^ permalink raw reply [flat|nested] 4+ messages in thread
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2013-11-27 7:54 ` [stable bug] NFSd NULL pointer trigger kernel panic Weng Meiling
2013-11-27 8:07 ` Stanislav Kinsbursky
2013-12-02 16:35 ` bfields
2013-12-03 1:24 ` Weng Meiling
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