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https://github.com/edk2-porting/linux-next.git
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ba3c6fb87d
BUG: unable to handle kernel NULL pointer dereference at 0000000000000058
IP: bd_release+0x21/0x70
Process drbd_w_t7146
Call Trace:
close_bdev_exclusive
drbd_free_ldev [drbd]
drbd_ldev_destroy [drbd]
w_after_state_ch [drbd]
Race probably went like this:
state.disk = D_FAILED
... first one to hit zero during D_FAILED:
put_ldev() /* ----------------> 0 */
i = atomic_dec_return()
if (i == 0)
if (state.disk == D_FAILED)
schedule_work(go_diskless)
/* 1 <------ */ get_ldev_if_state()
go_diskless()
do_some_pre_cleanup() corresponding put_ldev():
force_state(D_DISKLESS) /* 0 <------ */ i = atomic_dec_return()
if (i == 0)
atomic_inc() /* ---------> 1 */
state.disk = D_DISKLESS
schedule_work(after_state_ch) /* execution pre-empted by IRQ ? */
after_state_ch()
put_ldev()
i = atomic_dec_return() /* 0 */
if (i == 0)
if (state.disk == D_DISKLESS) if (state.disk == D_DISKLESS)
drbd_ldev_destroy() drbd_ldev_destroy();
Trying to fix this by checking the disk state *before* the
atomic_dec_return(), which implies memory barriers, and by inserting
extra memory barriers around the state assignment in __drbd_set_state().
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
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|---|---|---|
| .. | ||
| aoe | ||
| drbd | ||
| mtip32xx | ||
| paride | ||
| rsxx | ||
| xen-blkback | ||
| zram | ||
| amiflop.c | ||
| ataflop.c | ||
| brd.c | ||
| cciss_cmd.h | ||
| cciss_scsi.c | ||
| cciss_scsi.h | ||
| cciss.c | ||
| cciss.h | ||
| cpqarray.c | ||
| cpqarray.h | ||
| cryptoloop.c | ||
| DAC960.c | ||
| DAC960.h | ||
| floppy.c | ||
| hd.c | ||
| ida_cmd.h | ||
| ida_ioctl.h | ||
| Kconfig | ||
| loop.c | ||
| loop.h | ||
| Makefile | ||
| mg_disk.c | ||
| nbd.c | ||
| null_blk.c | ||
| nvme-core.c | ||
| nvme-scsi.c | ||
| osdblk.c | ||
| pktcdvd.c | ||
| ps3disk.c | ||
| ps3vram.c | ||
| rbd_types.h | ||
| rbd.c | ||
| skd_main.c | ||
| skd_s1120.h | ||
| smart1,2.h | ||
| sunvdc.c | ||
| swim3.c | ||
| swim_asm.S | ||
| swim.c | ||
| sx8.c | ||
| umem.c | ||
| umem.h | ||
| virtio_blk.c | ||
| xen-blkfront.c | ||
| xsysace.c | ||
| z2ram.c | ||