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authorLee Schermerhorn <Lee.Schermerhorn@hp.com>2007-09-21 08:33:55 +0200
committerJens Axboe <jens.axboe@oracle.com>2007-10-16 11:24:44 +0200
commita683d652d334a546be9175b894f42dbd8e399536 (patch)
tree26e9864495374d7d65afb3cd8a05c69f14f7f111 /drivers/block/cciss.c
parent2a7c59e79ce060c746358b08521de0acbca6a4f1 (diff)
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 <lee.schermerhorn@hp.com> drivers/block/cciss.c | 1 + 1 file changed, 1 insertion(+) Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'drivers/block/cciss.c')
-rw-r--r--drivers/block/cciss.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index 55c3237fb1b..2023d61d545 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -2570,6 +2570,7 @@ static void do_cciss_request(struct request_queue *q)
(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 */