Messages in this thread Patch in this message | | | From | Richard Weinberger <> | Subject | shm updates broke UML | Date | Mon, 1 Aug 2011 15:41:59 +0200 |
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Vasiliy,
5774ed01 (shm: handle separate PID namespaces case) b34a6b1d (ipc: introduce shm_rmid_forced sysctl) 4c677e2e (shm: optimize locking and ipc_namespace getting)
broke UML on i386. It crashes while starting up by SIGSEGV. exit_shm() seems to be the evil doer.
Reverting all three patches make UML work again.
Commit 5774ed01 removed the !ns->shm_rmid_forced check, maybe this is wrong? The attached patch cures the problem, but I'm sure it's wrong. 8)
---cut--- #13 0x08067efb in hard_handler (sig=11) at arch/um/os-Linux/sys-i386/signal.c:12 #14 <signal handler called> #15 __list_add (sem=0x824cc98, subclass=0) at include/linux/list.h:44 #16 list_add_tail (sem=0x824cc98, subclass=0) at include/linux/list.h:76 #17 __down_write_nested (sem=0x824cc98, subclass=0) at lib/rwsem-spinlock.c:232 #18 0x081c7ba1 in __down_write (sem=0x824cc98) at lib/rwsem-spinlock.c:252 #19 0x081c74a3 in down_write (sem=0x824cc98) at kernel/rwsem.c:51 #20 0x08139913 in exit_shm (task=0x9c73b60) at ipc/shm.c:308 #21 0x08075649 in do_exit (code=0) at kernel/exit.c:983 #22 0x08081dd2 in ____call_usermodehelper (data=0x9c6bce0) at kernel/kmod.c:187 #23 0x08065c18 in run_kernel_thread (fn=0x8081ce4 <____call_usermodehelper>, arg=0x9c6bce0, jmp_ptr=0x9c73d94) at arch/um/os-Linux/process.c:268 #24 0x080588cb in new_thread_handler () at arch/um/kernel/process.c:153 #25 0x00000000 in ?? () ---cut---
Not-Signed-off-by: Richard Weinberger <richard@nod.at> --- diff --git a/ipc/shm.c b/ipc/shm.c index 9fb044f3b..2196a0d 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -304,6 +304,9 @@ void exit_shm(struct task_struct *task) { struct ipc_namespace *ns = task->nsproxy->ipc_ns; + if(!ns->shm_rmid_forced) + return; + /* Destroy all already created segments, but not mapped yet */ down_write(&shm_ids(ns).rw_mutex); if (&shm_ids(ns).in_use)
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