4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Finn Thain fthain@telegraphics.com.au
commit 7ae6a2b6cc058005ee3d0d2b9ce27688e51afa4b upstream.
In the floppy_find() function in swim.c is a call to get_disk(swd->unit[drive].disk). The actual parameter to this call can be a NULL pointer when drive == swd->floppy_count. This causes an oops in get_disk().
Data read fault at 0x00000198 in Super Data (pc=0x1be5b6) BAD KERNEL BUSERR Oops: 00000000 Modules linked in: swim_mod ipv6 mac8390 PC: [<001be5b6>] get_disk+0xc/0x76 SR: 2004 SP: 9a078bc1 a2: 0213ed90 d0: 00000000 d1: 00000000 d2: 00000000 d3: 000000ff d4: 00000002 d5: 02983590 a0: 02332e00 a1: 022dfd64 Process dd (pid: 285, task=020ab25b) Frame format=B ssw=074d isc=4a88 isb=6732 daddr=00000198 dobuf=00000000 baddr=001be5bc dibuf=bfffffff ver=f Stack from 022dfca4: 00000000 0203fc00 0213ed90 022dfcc0 02982936 00000000 00200000 022dfd08 0020f85a 00200000 022dfd64 02332e00 004040fc 00000014 001be77e 022dfd64 00334e4a 001be3f8 0800001d 022dfd64 01c04b60 01c04b70 022aba80 029828f8 02332e00 022dfd2c 001be7ac 0203fc00 00200000 022dfd64 02103a00 01c04b60 01c04b60 0200e400 022dfd68 000e191a 00200000 022dfd64 02103a00 0800001d 00000000 00000003 000b89de 00500000 02103a00 01c04b60 02103a08 01c04c2e Call Trace: [<02982936>] floppy_find+0x3e/0x4a [swim_mod] [<00200000>] uart_remove_one_port+0x1a2/0x260 [<0020f85a>] kobj_lookup+0xde/0x132 [<00200000>] uart_remove_one_port+0x1a2/0x260 [<001be77e>] get_gendisk+0x0/0x130 [<00334e4a>] mutex_lock+0x0/0x2e [<001be3f8>] disk_block_events+0x0/0x6c [<029828f8>] floppy_find+0x0/0x4a [swim_mod] [<001be7ac>] get_gendisk+0x2e/0x130 [<00200000>] uart_remove_one_port+0x1a2/0x260 [<000e191a>] __blkdev_get+0x32/0x45a [<00200000>] uart_remove_one_port+0x1a2/0x260 [<000b89de>] complete_walk+0x0/0x8a [<000e1e22>] blkdev_get+0xe0/0x29a [<000e1fdc>] blkdev_open+0x0/0xb0 [<000b89de>] complete_walk+0x0/0x8a [<000e1fdc>] blkdev_open+0x0/0xb0 [<000e01cc>] bd_acquire+0x74/0x8a [<000e205c>] blkdev_open+0x80/0xb0 [<000e1fdc>] blkdev_open+0x0/0xb0 [<000abf24>] do_dentry_open+0x1a4/0x322 [<00020000>] __do_proc_douintvec+0x22/0x27e [<000b89de>] complete_walk+0x0/0x8a [<000baa62>] link_path_walk+0x0/0x48e [<000ba3f8>] inode_permission+0x20/0x54 [<000ac0e4>] vfs_open+0x42/0x78 [<000bc372>] path_openat+0x2b2/0xeaa [<000bc0c0>] path_openat+0x0/0xeaa [<0004463e>] __irq_wake_thread+0x0/0x4e [<0003a45a>] task_tick_fair+0x18/0xc8 [<000bd00a>] do_filp_open+0xa0/0xea [<000abae0>] do_sys_open+0x11a/0x1ee [<00020000>] __do_proc_douintvec+0x22/0x27e [<000abbf4>] SyS_open+0x1e/0x22 [<00020000>] __do_proc_douintvec+0x22/0x27e [<00002b40>] syscall+0x8/0xc [<00020000>] __do_proc_douintvec+0x22/0x27e [<0000c00b>] dyadic+0x1/0x28 Code: 4e5e 4e75 4e56 fffc 2f0b 2f02 266e 0008 <206b> 0198 4a88 6732 2428 002c 661e 486b 0058 4eb9 0032 0b96 588f 4a88 672c 2008 Disabling lock debugging due to kernel taint
Fix the array index bounds check to avoid this.
Cc: Laurent Vivier lvivier@redhat.com Cc: Jens Axboe axboe@kernel.dk Cc: stable@vger.kernel.org # v4.14+ Fixes: 8852ecd97488 ("[PATCH] m68k: mac - Add SWIM floppy support") Tested-by: Stan Johnson userm57@yahoo.com Signed-off-by: Finn Thain fthain@telegraphics.com.au Acked-by: Laurent Vivier lvivier@redhat.com Reviewed-by: Geert Uytterhoeven geert@linux-m68k.org Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/block/swim.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/block/swim.c +++ b/drivers/block/swim.c @@ -790,7 +790,7 @@ static struct kobject *floppy_find(dev_t struct swim_priv *swd = data; int drive = (*part & 3);
- if (drive > swd->floppy_count) + if (drive >= swd->floppy_count) return NULL;
*part = 0;