linux-hardened/drivers/mtd/ubi
Rabin Vincent 8a1435880f ubi: fastmap: Fix slab corruption
Booting with UBI fastmap and SLUB debugging enabled results in the
following splats.  The problem is that ubi_scan_fastmap() moves the
fastmap blocks from the scan_ai (allocated in scan_fast()) to the ai
allocated in ubi_attach().  This results in two problems:

 - When the scan_ai is freed, aebs which were allocated from its slab
   cache are still in use.

 - When the other ai is being destroyed in destroy_ai(), the
   arguments to kmem_cache_free() call are incorrect since aebs on its
   ->fastmap list were allocated with a slab cache from a differnt ai.

Fix this by making a copy of the aebs in ubi_scan_fastmap() instead of
moving them.

 =============================================================================
 BUG ubi_aeb_slab_cache (Not tainted): Objects remaining in ubi_aeb_slab_cache on __kmem_cache_shutdown()
 -----------------------------------------------------------------------------

 INFO: Slab 0xbfd2da3c objects=17 used=1 fp=0xb33d7748 flags=0x40000080
 CPU: 1 PID: 118 Comm: ubiattach Tainted: G    B           4.9.15 #3
 [<80111910>] (unwind_backtrace) from [<8010d498>] (show_stack+0x18/0x1c)
 [<8010d498>] (show_stack) from [<804a3274>] (dump_stack+0xb4/0xe0)
 [<804a3274>] (dump_stack) from [<8026c47c>] (slab_err+0x78/0x88)
 [<8026c47c>] (slab_err) from [<802735bc>] (__kmem_cache_shutdown+0x180/0x3e0)
 [<802735bc>] (__kmem_cache_shutdown) from [<8024e13c>] (shutdown_cache+0x1c/0x60)
 [<8024e13c>] (shutdown_cache) from [<8024ed64>] (kmem_cache_destroy+0x19c/0x20c)
 [<8024ed64>] (kmem_cache_destroy) from [<8057cc14>] (destroy_ai+0x1dc/0x1e8)
 [<8057cc14>] (destroy_ai) from [<8057f04c>] (ubi_attach+0x3f4/0x450)
 [<8057f04c>] (ubi_attach) from [<8056fe70>] (ubi_attach_mtd_dev+0x60c/0xff8)
 [<8056fe70>] (ubi_attach_mtd_dev) from [<80571d78>] (ctrl_cdev_ioctl+0x110/0x2b8)
 [<80571d78>] (ctrl_cdev_ioctl) from [<8029c77c>] (do_vfs_ioctl+0xac/0xa00)
 [<8029c77c>] (do_vfs_ioctl) from [<8029d10c>] (SyS_ioctl+0x3c/0x64)
 [<8029d10c>] (SyS_ioctl) from [<80108860>] (ret_fast_syscall+0x0/0x1c)
 INFO: Object 0xb33d7e88 @offset=3720
 INFO: Allocated in scan_peb+0x608/0x81c age=72 cpu=1 pid=118
 	kmem_cache_alloc+0x3b0/0x43c
 	scan_peb+0x608/0x81c
 	ubi_attach+0x124/0x450
 	ubi_attach_mtd_dev+0x60c/0xff8
 	ctrl_cdev_ioctl+0x110/0x2b8
 	do_vfs_ioctl+0xac/0xa00
 	SyS_ioctl+0x3c/0x64
 	ret_fast_syscall+0x0/0x1c
 kmem_cache_destroy ubi_aeb_slab_cache: Slab cache still has objects
 CPU: 1 PID: 118 Comm: ubiattach Tainted: G    B           4.9.15 #3
 [<80111910>] (unwind_backtrace) from [<8010d498>] (show_stack+0x18/0x1c)
 [<8010d498>] (show_stack) from [<804a3274>] (dump_stack+0xb4/0xe0)
 [<804a3274>] (dump_stack) from [<8024ed80>] (kmem_cache_destroy+0x1b8/0x20c)
 [<8024ed80>] (kmem_cache_destroy) from [<8057cc14>] (destroy_ai+0x1dc/0x1e8)
 [<8057cc14>] (destroy_ai) from [<8057f04c>] (ubi_attach+0x3f4/0x450)
 [<8057f04c>] (ubi_attach) from [<8056fe70>] (ubi_attach_mtd_dev+0x60c/0xff8)
 [<8056fe70>] (ubi_attach_mtd_dev) from [<80571d78>] (ctrl_cdev_ioctl+0x110/0x2b8)
 [<80571d78>] (ctrl_cdev_ioctl) from [<8029c77c>] (do_vfs_ioctl+0xac/0xa00)
 [<8029c77c>] (do_vfs_ioctl) from [<8029d10c>] (SyS_ioctl+0x3c/0x64)
 [<8029d10c>] (SyS_ioctl) from [<80108860>] (ret_fast_syscall+0x0/0x1c)
 cache_from_obj: Wrong slab cache. ubi_aeb_slab_cache but object is from ubi_aeb_slab_cache
 ------------[ cut here ]------------
 WARNING: CPU: 1 PID: 118 at mm/slab.h:354 kmem_cache_free+0x39c/0x450
 Modules linked in:
 CPU: 1 PID: 118 Comm: ubiattach Tainted: G    B           4.9.15 #3
 [<80111910>] (unwind_backtrace) from [<8010d498>] (show_stack+0x18/0x1c)
 [<8010d498>] (show_stack) from [<804a3274>] (dump_stack+0xb4/0xe0)
 [<804a3274>] (dump_stack) from [<80120e40>] (__warn+0xf4/0x10c)
 [<80120e40>] (__warn) from [<80120f20>] (warn_slowpath_null+0x28/0x30)
 [<80120f20>] (warn_slowpath_null) from [<80271fe0>] (kmem_cache_free+0x39c/0x450)
 [<80271fe0>] (kmem_cache_free) from [<8057cb88>] (destroy_ai+0x150/0x1e8)
 [<8057cb88>] (destroy_ai) from [<8057ef1c>] (ubi_attach+0x2c4/0x450)
 [<8057ef1c>] (ubi_attach) from [<8056fe70>] (ubi_attach_mtd_dev+0x60c/0xff8)
 [<8056fe70>] (ubi_attach_mtd_dev) from [<80571d78>] (ctrl_cdev_ioctl+0x110/0x2b8)
 [<80571d78>] (ctrl_cdev_ioctl) from [<8029c77c>] (do_vfs_ioctl+0xac/0xa00)
 [<8029c77c>] (do_vfs_ioctl) from [<8029d10c>] (SyS_ioctl+0x3c/0x64)
 [<8029d10c>] (SyS_ioctl) from [<80108860>] (ret_fast_syscall+0x0/0x1c)
 ---[ end trace 2bd8396277fd0a0b ]---
 =============================================================================
 BUG ubi_aeb_slab_cache (Tainted: G    B   W      ): page slab pointer corrupt.
 -----------------------------------------------------------------------------

 INFO: Allocated in scan_peb+0x608/0x81c age=104 cpu=1 pid=118
 	kmem_cache_alloc+0x3b0/0x43c
 	scan_peb+0x608/0x81c
 	ubi_attach+0x124/0x450
 	ubi_attach_mtd_dev+0x60c/0xff8
 	ctrl_cdev_ioctl+0x110/0x2b8
 	do_vfs_ioctl+0xac/0xa00
 	SyS_ioctl+0x3c/0x64
 	ret_fast_syscall+0x0/0x1c
 INFO: Slab 0xbfd2da3c objects=17 used=1 fp=0xb33d7748 flags=0x40000081
 INFO: Object 0xb33d7e88 @offset=3720 fp=0xb33d7da0

 Redzone b33d7e80: cc cc cc cc cc cc cc cc                          ........
 Object b33d7e88: 02 00 00 00 01 00 00 00 00 f0 ff 7f ff ff ff ff  ................
 Object b33d7e98: 00 00 00 00 00 00 00 00 bd 16 00 00 00 00 00 00  ................
 Object b33d7ea8: 00 01 00 00 00 02 00 00 00 00 00 00 00 00 00 00  ................
 Redzone b33d7eb8: cc cc cc cc                                      ....
 Padding b33d7f60: 5a 5a 5a 5a 5a 5a 5a 5a                          ZZZZZZZZ
 CPU: 1 PID: 118 Comm: ubiattach Tainted: G    B   W       4.9.15 #3
 [<80111910>] (unwind_backtrace) from [<8010d498>] (show_stack+0x18/0x1c)
 [<8010d498>] (show_stack) from [<804a3274>] (dump_stack+0xb4/0xe0)
 [<804a3274>] (dump_stack) from [<80271770>] (free_debug_processing+0x320/0x3c4)
 [<80271770>] (free_debug_processing) from [<80271ad0>] (__slab_free+0x2bc/0x430)
 [<80271ad0>] (__slab_free) from [<80272024>] (kmem_cache_free+0x3e0/0x450)
 [<80272024>] (kmem_cache_free) from [<8057cb88>] (destroy_ai+0x150/0x1e8)
 [<8057cb88>] (destroy_ai) from [<8057ef1c>] (ubi_attach+0x2c4/0x450)
 [<8057ef1c>] (ubi_attach) from [<8056fe70>] (ubi_attach_mtd_dev+0x60c/0xff8)
 [<8056fe70>] (ubi_attach_mtd_dev) from [<80571d78>] (ctrl_cdev_ioctl+0x110/0x2b8)
 [<80571d78>] (ctrl_cdev_ioctl) from [<8029c77c>] (do_vfs_ioctl+0xac/0xa00)
 [<8029c77c>] (do_vfs_ioctl) from [<8029d10c>] (SyS_ioctl+0x3c/0x64)
 [<8029d10c>] (SyS_ioctl) from [<80108860>] (ret_fast_syscall+0x0/0x1c)
 FIX ubi_aeb_slab_cache: Object at 0xb33d7e88 not freed

Signed-off-by: Rabin Vincent <rabinv@axis.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
2017-05-08 20:48:33 +02:00
..
attach.c UBI: introduce the VID buffer concept 2016-10-02 22:48:14 +02:00
block.c block: fold cmd_type into the REQ_OP_ space 2017-01-31 14:00:44 -07:00
build.c ubi: Make mtd parameter readable 2017-05-08 20:48:17 +02:00
cdev.c UBI: add an helper to check lnum validity 2016-10-02 22:48:14 +02:00
debug.c UBI: Silence an unintialized variable warning 2016-05-24 15:24:30 +02:00
debug.h UBI: power cut emulation for testing 2015-04-13 21:05:17 +02:00
eba.c UBI: Fix crash in try_recover_peb() 2016-10-20 00:06:06 +02:00
fastmap-wl.c ubi: Fix races around ubi_refill_pools() 2016-10-02 22:54:01 +02:00
fastmap.c ubi: fastmap: Fix slab corruption 2017-05-08 20:48:33 +02:00
gluebi.c ubi: gluebi: Fix double refcounting 2016-07-29 23:31:54 +02:00
io.c UBI: introduce the VID buffer concept 2016-10-02 22:48:14 +02:00
kapi.c statx: Add a system call to make enhanced file info available 2017-03-02 20:51:15 -05:00
Kconfig UBI: block: Add CONFIG_BLOCK dependency 2014-03-04 14:49:53 +02:00
Makefile UBI: R/O block driver on top of UBI volumes 2014-02-28 16:29:48 +02:00
misc.c mtd: ubi: Add logging functions ubi_msg, ubi_warn and ubi_err 2016-03-20 21:36:05 +01:00
ubi-media.h UBI: Fix typo in comment 2015-10-03 20:09:41 +02:00
ubi.h UBI: introduce the VID buffer concept 2016-10-02 22:48:14 +02:00
upd.c ubi/upd: Always flush after prepared for an update 2017-03-30 09:27:11 +02:00
vmt.c UBI: hide EBA internals 2016-10-02 22:48:14 +02:00
vtbl.c UBI: introduce the VID buffer concept 2016-10-02 22:48:14 +02:00
wl.c ubi: Fix races around ubi_refill_pools() 2016-10-02 22:54:01 +02:00
wl.h UBI: Fastmap: Remove is_fm_block() 2015-03-26 22:47:38 +01:00