On Thu, Sep 20 2007, Lee Schermerhorn wrote: > PATCH 2.6.23-rc6-mm1 - Panic in blk_rq_map_sg() from CCISS driver > > New scatter/gather list chaining [sg_next()] treats 'page' member of > struct scatterlist with low bit set [0x01] as a chain pointer to > another struct scatterlist [array]. The CCISS driver request function > passes an uninitialized, temporary, on-stack scatterlist array to > blk_rq_map_sq(). sg_next() interprets random data on the stack as a > chain pointer and eventually tries to de-reference an invalid pointer, > resulting in: > > [<ffffffff8031dd70>] blk_rq_map_sg+0x70/0x170 > PGD 6090c3067 PUD 0 > Oops: 0000 [1] SMP > last sysfs file: /block/cciss!c0d0/cciss!c0d0p1/dev > CPU 6 > Modules linked in: ehci_hcd ohci_hcd uhci_hcd > Pid: 1, comm: init Not tainted 2.6.23-rc6-mm1 #3 > RIP: 0010:[<ffffffff8031dd70>] [<ffffffff8031dd70>] blk_rq_map_sg+0x70/0x170 > RSP: 0018:ffff81060901f768 EFLAGS: 00010206 > RAX: 000000040b161000 RBX: ffff81060901f7d8 RCX: 000000040b162c00 > RDX: 0000000000000000 RSI: ffff81060b13a260 RDI: ffff81060b139600 > RBP: 0000000000001400 R08: 00000000fffffffe R09: 0000000000000400 > R10: 0000000000000000 R11: 000000040b163000 R12: ffff810102fe0000 > R13: 0000000000000001 R14: 0000000000000001 R15: 00001e0000000000 > FS: 00000000026108f0(0063) GS:ffff810409000b80(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > CR2: 000000010000001e CR3: 00000006090c6000 CR4: 00000000000006e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > Process init (pid: 1, threadinfo ffff81060901e000, task ffff810409020800) > last branch before last exception/interrupt > from [<ffffffff8031de0a>] blk_rq_map_sg+0x10a/0x170 > to [<ffffffff8031dd70>] blk_rq_map_sg+0x70/0x170 > Stack: 000000018068ea00 ffff810102fe0000 0000000000000000 ffff810011400000 > 0000000000000002 0000000000000000 ffff81040b172000 ffffffff803acd3d > 0000000000003ec1 ffff8106090d5000 ffff8106090d5000 ffff810102fe0000 > Call Trace: > [<ffffffff803acd3d>] do_cciss_request+0x15d/0x4c0 > [<ffffffff80298968>] new_slab+0x1c8/0x270 > [<ffffffff80298ffd>] __slab_alloc+0x22d/0x470 > [<ffffffff8027327b>] mempool_alloc+0x4b/0x130 > [<ffffffff8032b21e>] cfq_set_request+0xee/0x380 > [<ffffffff8027327b>] mempool_alloc+0x4b/0x130 > [<ffffffff8031ff98>] get_request+0x168/0x360 > [<ffffffff80331b0d>] rb_insert_color+0x8d/0x110 > [<ffffffff8031cfd8>] elv_rb_add+0x58/0x60 > [<ffffffff8032a329>] cfq_add_rq_rb+0x69/0xa0 > [<ffffffff8031c1ab>] elv_merged_request+0x5b/0x60 > [<ffffffff803224fd>] __make_request+0x23d/0x650 > [<ffffffff80298ffd>] __slab_alloc+0x22d/0x470 > [<ffffffff80270000>] generic_write_checks+0x140/0x190 > [<ffffffff8031f012>] generic_make_request+0x1c2/0x3a0 > <etc> > Kernel panic - not syncing: Attempted to kill init! > > This patch initializes the tmp_sg array to zeroes. Perhaps not the ultimate > fix, but an effective work-around. I can now boot 23-rc6-mm1 on an HP > Proliant x86_64 with CCISS boot disk. > > Signed-off-by: Lee Schermerhorn <[EMAIL PROTECTED]> > > drivers/block/cciss.c | 1 + > 1 file changed, 1 insertion(+) > > Index: Linux/drivers/block/cciss.c > =================================================================== > --- Linux.orig/drivers/block/cciss.c 2007-09-20 14:59:29.000000000 -0400 > +++ Linux/drivers/block/cciss.c 2007-09-20 15:06:39.000000000 -0400 > @@ -2611,6 +2611,7 @@ static void do_cciss_request(struct requ > (int)creq->nr_sectors); > #endif /* CCISS_DEBUG */ > > + memset(tmp_sg, 0, sizeof(tmp_sg)); > seg = blk_rq_map_sg(q, creq, tmp_sg); > > /* get the DMA records for the setup */ >
Thanks Lee, applied. -- Jens Axboe - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
