Messages in this thread | | | Subject | Re: [ipc,shm] BUG: lock held when returning to user space! | From | Davidlohr Bueso <> | Date | Sat, 20 Jul 2013 09:46:45 -0700 |
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On Sun, 2013-07-21 at 00:02 +0800, Xiaotian Feng wrote: > On Sat, Jul 20, 2013 at 9:13 PM, Fengguang Wu <fengguang.wu@intel.com> wrote: > > Greetings, > > > > I got the below dmesg and the first bad commit is > > > > commit c5d0282a0405b0a81fa3390e4230e4cbb3ced7a2 > > Author: Davidlohr Bueso <davidlohr.bueso@hp.com> > > Date: Fri Jul 19 09:56:58 2013 +1000 > > > > ipc,shm: shorten critical region for shmat > > > > Similar to other system calls, acquire the kern_ipc_perm lock after doing > > the initial permission and security checks. > > > > Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com> > > Tested-by: Sedat Dilek <sedat.dilek@gmail.com> > > Cc: Rik van Riel <riel@redhat.com> > > Cc: Manfred Spraul <manfred@colorfullife.com> > > Signed-off-by: Andrew Morton <akpm@linux-foundation.org> > > > > [ 20.702156] > > [ 20.702493] ================================================ > > [ 20.703511] [ BUG: lock held when returning to user space! ] > > [ 20.704532] 3.11.0-rc1-next-20130719 #50 Not tainted > > [ 20.705416] ------------------------------------------------ > > [ 20.706425] trinity-child0/174 is leaving the kernel with locks still held! > > [ 20.707638] 1 lock held by trinity-child0/174: > > [ 20.708475] #0: (rcu_read_lock){.+.+..}, at: [<ffffffff814a8491>] do_shmat+0xe1/0x500 > > > > ---- > ns = current->nsproxy->ipc_ns; > - shp = shm_lock_check(ns, shmid); > + rcu_read_lock(); > + shp = shm_obtain_object_check(ns, shmid); > if (IS_ERR(shp)) { > err = PTR_ERR(shp); > goto out; > ---- > > If shm_obtain_object_check() failed, goto out will return with > rcu_read_lock() held. I think following patch should cure this.
Yep that should solve it, sorry about that. Sasha Levin sent out a fix for it yesterday (offline).
Thanks, Davidlohr
> > diff --git a/ipc/shm.c b/ipc/shm.c > index 59f2194..cb2ceda 100644 > --- a/ipc/shm.c > +++ b/ipc/shm.c > @@ -1093,7 +1093,7 @@ long do_shmat(int shmid, char __user *shmaddr, > int shmflg, ulong *raddr, > shp = shm_obtain_object_check(ns, shmid); > if (IS_ERR(shp)) { > err = PTR_ERR(shp); > - goto out; > + goto out_unlock; > } > > err = -EACCES; > > > > > > git bisect start c1f631b9a68251007a6353041ae90f9f7dca771c d03792f9db9b892f494d3aa19d767ddf0365d1ff -- > > git bisect good 10a3f1f902465ae1320cc95a3284fd3697e05dd8 # 11:14 65+ binfmt_elf.c: use get_random_int() to fix entropy depleting > > git bisect bad dac28788378838efb63e37a7eabd7729d97aba6b # 11:32 0- dcache: remove dentries from LRU before putting on dispose list > > git bisect good 3140b2ed6dfe5c9e5eca371c77ca85dca05321d4 # 11:50 65+ ipc,shm: introduce shmctl_nolock > > git bisect bad 48a91248649fa3327bd8a31c114ee9149a07f3a7 # 12:04 0- staging/lustre/ldlm: convert to shrinkers to count/scan API > > git bisect good 98b78126a51aa5d3ee6d5dae5768e0d16deeeaa3 # 12:14 65+ ipc,shm: cleanup do_shmat pasta > > git bisect bad 36ccfd799cad33e2edd5c14ac8776b33e63d195b # 12:14 0- ipc: rename ids->rw_mutex > > git bisect bad c5d0282a0405b0a81fa3390e4230e4cbb3ced7a2 # 12:14 0- ipc,shm: shorten critical region for shmat > > git bisect good 98b78126a51aa5d3ee6d5dae5768e0d16deeeaa3 # 15:34 195+ ipc,shm: cleanup do_shmat pasta > > git bisect bad c1f631b9a68251007a6353041ae90f9f7dca771c # 15:34 0- Add linux-next specific files for 20130719 > > git bisect good 709b465ee655387c4ec056383fa27f16c64f48db # 18:21 195+ Revert "ipc,shm: shorten critical region for shmat" > > git bisect good d471ce53b1fab60110e4e9f647a345cea31752de # 18:44 195+ Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml > > git bisect bad c1f631b9a68251007a6353041ae90f9f7dca771c # 18:44 0- Add linux-next specific files for 20130719 > > > > Thanks, > > Fengguang
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