Messages in this thread | | | From | Andreas Gruenbacher <> | Date | Wed, 26 Oct 2016 14:51:57 +0200 | Subject | CONFIG_VMAP_STACK, on-stack struct, and wake_up_bit |
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Hi,
CONFIG_VMAP_STACK has broken gfs2 and I'm trying to figure out what's going on. What I'm seeing is the following: on a fresh gfs2 filesystem created with:
mkfs.gfs2 -p lock_nolock $DEVICE
I get the following BUG with 4.9-rc2, CONFIG_VMAP_STACK and CONFIG_DEBUG_VIRTUAL turned on:
kernel BUG at arch/x86/mm/physaddr.c:26!
Stack of kernel thread:
__phys_addr(x) bit_waitqueue(word, bit) wake_up_bit(word = &gh->gh_iflags, bit = HIF_WAIT) gfs2_holder_wake(gh)
The gh here is on the stack of another kernel thread:
static int fill_super(struct super_block *sb, struct gfs2_args *args, int silent) { struct gfs2_holder mount_gh; }
Which is waiting on the bit with:
wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE)
Is accessing a struct on another kernel thread's stack no longer working?
Thanks, Andreas
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