On 10/21/19 10:29 AM, Mark Salter wrote: > A NULL-pointer dereference was reported in fedora bz#1762199 while > reshaping a raid6 array after adding a fifth drive to an existing > array. > > [ 47.343549] md/raid:md0: raid level 6 active with 3 out of 5 devices, algorithm 2 > [ 47.804017] md0: detected capacity change from 0 to 7885289422848 > [ 47.822083] Unable to handle kernel read from unreadable memory at virtual address 0000000000000000 > ... > [ 47.940477] CPU: 1 PID: 14210 Comm: md0_raid6 Tainted: G W 5.2.18-200.fc30.aarch64 #1 > [ 47.949594] Hardware name: AMD Overdrive/Supercharger/To be filled by O.E.M., BIOS ROD1002C 04/08/2016 > [ 47.958886] pstate: 00400085 (nzcv daIf +PAN -UAO) > [ 47.963668] pc : __list_del_entry_valid+0x2c/0xa8 > [ 47.968366] lr : ccp_tx_submit+0x84/0x168 [ccp] > [ 47.972882] sp : ffff00001369b970 > [ 47.976184] x29: ffff00001369b970 x28: ffff00001369bdb8 > [ 47.981483] x27: 00000000ffffffff x26: ffff8003b758af70 > [ 47.986782] x25: ffff8003b758b2d8 x24: ffff8003e6245818 > [ 47.992080] x23: 0000000000000000 x22: ffff8003e62450c0 > [ 47.997379] x21: ffff8003dfd6add8 x20: 0000000000000003 > [ 48.002678] x19: ffff8003e6245100 x18: 0000000000000000 > [ 48.007976] x17: 0000000000000000 x16: 0000000000000000 > [ 48.013274] x15: 0000000000000000 x14: 0000000000000000 > [ 48.018572] x13: ffff7e000ef83a00 x12: 0000000000000001 > [ 48.023870] x11: ffff000010eff998 x10: 00000000000019a0 > [ 48.029169] x9 : 0000000000000000 x8 : ffff8003e6245180 > [ 48.034467] x7 : 0000000000000000 x6 : 000000000000003f > [ 48.039766] x5 : 0000000000000040 x4 : ffff8003e0145080 > [ 48.045064] x3 : dead000000000200 x2 : 0000000000000000 > [ 48.050362] x1 : 0000000000000000 x0 : ffff8003e62450c0 > [ 48.055660] Call trace: > [ 48.058095] __list_del_entry_valid+0x2c/0xa8 > [ 48.062442] ccp_tx_submit+0x84/0x168 [ccp] > [ 48.066615] async_tx_submit+0x224/0x368 [async_tx] > [ 48.071480] async_trigger_callback+0x68/0xfc [async_tx] > [ 48.076784] ops_run_biofill+0x178/0x1e8 [raid456] > [ 48.081566] raid_run_ops+0x248/0x818 [raid456] > [ 48.086086] handle_stripe+0x864/0x1208 [raid456] > [ 48.090781] handle_active_stripes.isra.0+0xb0/0x278 [raid456] > [ 48.096604] raid5d+0x378/0x618 [raid456] > [ 48.100602] md_thread+0xa0/0x150 > [ 48.103905] kthread+0x104/0x130 > [ 48.107122] ret_from_fork+0x10/0x18 > [ 48.110686] Code: d2804003 f2fbd5a3 eb03003f 54000320 (f9400021) > [ 48.116766] ---[ end trace 23f390a527f7ad77 ]--- > > ccp_tx_submit is passed a dma_async_tx_descriptor which is contained in > a ccp_dma_desc and adds it to a ccp channel's pending list: > > list_del(&desc->entry); > list_add_tail(&desc->entry, &chan->pending); > > The problem is that desc->entry may be uninitialized in the > async_trigger_callback path where the descriptor was gotten > from ccp_prep_dma_interrupt which got it from ccp_alloc_dma_desc > which doesn't initialize the desc->entry list head. So, just > initialize the list head to avoid the problem. > > Reported-by: Sahaj Sarup <sahajsarup@xxxxxxxxx> > Signed-off-by: Mark Salter <msalter@xxxxxxxxxx> Acked-by: Gary R Hook <gary.hook@xxxxxxx> > --- > drivers/crypto/ccp/ccp-dmaengine.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/crypto/ccp/ccp-dmaengine.c b/drivers/crypto/ccp/ccp-dmaengine.c > index a54f9367a580..0770a83bf1a5 100644 > --- a/drivers/crypto/ccp/ccp-dmaengine.c > +++ b/drivers/crypto/ccp/ccp-dmaengine.c > @@ -342,6 +342,7 @@ static struct ccp_dma_desc *ccp_alloc_dma_desc(struct ccp_dma_chan *chan, > desc->tx_desc.flags = flags; > desc->tx_desc.tx_submit = ccp_tx_submit; > desc->ccp = chan->ccp; > + INIT_LIST_HEAD(&desc->entry); > INIT_LIST_HEAD(&desc->pending); > INIT_LIST_HEAD(&desc->active); > desc->status = DMA_IN_PROGRESS; >
