On Tue, 2012-01-24 at 13:40 -0500, Mimi Zohar wrote: > On Tue, 2012-01-24 at 12:45 -0500, Eric Paris wrote: > > On Tue, 2012-01-24 at 12:34 -0500, Mimi Zohar wrote: > > > The circular lockdep is caused by allocating the 'iint' for mmapped > > > files. Originally when an 'iint' was allocated for every inode > > > in inode_alloc_security(), before the inode was accessible, no > > > locking was necessary. Commits bc7d2a3e and 196f518 changed this > > > behavior and allocated the 'iint' on a per need basis, resulting in > > > the mmap_sem being taken before the i_mutex for mmapped files. > > > > > > Possible unsafe locking scenario: > > > CPU0 CPU1 > > > ---- ---- > > > lock(&mm->mmap_sem); > > > lock(&sb->s_type->i_mutex_key); > > > lock(&mm->mmap_sem); > > > lock(&sb->s_type->i_mutex_key); > > > > > > The existing security_file_mmap() hook is after the mmap_sem is taken. > > > This patch moves the ima_file_mmap() call from security_file_mmap() to > > > prior to the mmap_sem being taken. > > > > > > Changelog v1: > > > - Instead of just pre-allocating the iint in a new hook, do ALL of the > > > work in the new/moved ima_file_mmap() hook. (Based on Eric Paris' suggestion.) > > > - Removed do_mmap_with_sem() helper function. > > > - export ima_file_mmap() > > > > Why does it need to be exported? What module might call this? > > Without it, I'm getting: > > Kernel: arch/x86/boot/bzImage is ready (#246) > ERROR: "ima_file_mmap" [arch/x86/ia32/ia32_aout.ko] undefined! > make[1]: *** [__modpost] Error 1 > make: *** [modules] Error 2 Ok, that's what I was wondering (and guessing). Sorry! Acked-by: Eric Paris <eparis@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
