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f84adf4921
Replace llist_for_each_entry_safe with a while loop. llist_for_each_entry_safe can trigger a bug in GCC 4.1, so it's best to remove it and use a while loop and do the deletion manually. Specifically this bug can be triggered by hot-unplugging a disk, either by doing xm block-detach or by save/restore cycle. BUG: unable to handle kernel paging request at fffffffffffffff0 IP: [<ffffffffa0047223>] blkif_free+0x63/0x130 [xen_blkfront] The crash call trace is: ... bad_area_nosemaphore+0x13/0x20 do_page_fault+0x25e/0x4b0 page_fault+0x25/0x30 ? blkif_free+0x63/0x130 [xen_blkfront] blkfront_resume+0x46/0xa0 [xen_blkfront] xenbus_dev_resume+0x6c/0x140 pm_op+0x192/0x1b0 device_resume+0x82/0x1e0 dpm_resume+0xc9/0x1a0 dpm_resume_end+0x15/0x30 do_suspend+0x117/0x1e0 When drilling down to the assembler code, on newer GCC it does .L29: cmpq $-16, %r12 #, persistent_gnt check je .L30 #, out of the loop .L25: ... code in the loop testq %r13, %r13 # n je .L29 #, back to the top of the loop cmpq $-16, %r12 #, persistent_gnt check movq 16(%r12), %r13 # <variable>.node.next, n jne .L25 #, back to the top of the loop .L30: While on GCC 4.1, it is: L78: ... code in the loop testq %r13, %r13 # n je .L78 #, back to the top of the loop movq 16(%rbx), %r13 # <variable>.node.next, n jmp .L78 #, back to the top of the loop Which basically means that the exit loop condition instead of being: &(pos)->member != NULL; is: ; which makes the loop unbound. Since xen-blkfront is the only user of the llist_for_each_entry_safe macro remove it from llist.h. Orabug: 16263164 CC: stable@vger.kernel.org Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> |
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.. | ||
aoe | ||
drbd | ||
mtip32xx | ||
paride | ||
xen-blkback | ||
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 | ||
Makefile | ||
mg_disk.c | ||
nbd.c | ||
nvme.c | ||
osdblk.c | ||
pktcdvd.c | ||
ps3disk.c | ||
ps3vram.c | ||
rbd_types.h | ||
rbd.c | ||
smart1,2.h | ||
sunvdc.c | ||
swim3.c | ||
swim_asm.S | ||
swim.c | ||
sx8.c | ||
umem.c | ||
umem.h | ||
virtio_blk.c | ||
xd.c | ||
xd.h | ||
xen-blkfront.c | ||
xsysace.c | ||
z2ram.c |