kernel.git/drivers/mtd/ubi/fastmap.c, branch linux-3.18.y

UBI: fastmap: scrub PEB when bitflips are detected in a free PEB EC header

2017-04-18T05:55:45Z

commit ecbfa8eabae9cd73522d1d3d15869703c263d859 upstream. scan_pool() does not mark the PEB for scrubing when bitflips are detected in the EC header of a free PEB (VID header region left to 0xff). Make sure we scrub the PEB in this case. Signed-off-by: Boris Brezillon Fixes: dbb7d2a88d2a ("UBI: Add fastmap core") Signed-off-by: Richard Weinberger Signed-off-by: Greg Kroah-Hartman

UBI: Fix static volume checks when Fastmap is used

2016-06-06T23:11:13Z

[ Upstream commit 1900149c835ab5b48bea31a823ea5e5a401fb560 ] Ezequiel reported that he's facing UBI going into read-only mode after power cut. It turned out that this behavior happens only when updating a static volume is interrupted and Fastmap is used. A possible trace can look like: ubi0 warning: ubi_io_read_vid_hdr [ubi]: no VID header found at PEB 2323, only 0xFF bytes ubi0 warning: ubi_eba_read_leb [ubi]: switch to read-only mode CPU: 0 PID: 833 Comm: ubiupdatevol Not tainted 4.6.0-rc2-ARCH #4 Hardware name: SAMSUNG ELECTRONICS CO., LTD. 300E4C/300E5C/300E7C/NP300E5C-AD8AR, BIOS P04RAP 10/15/2012 0000000000000286 00000000eba949bd ffff8800c45a7b38 ffffffff8140d841 ffff8801964be000 ffff88018eaa4800 ffff8800c45a7bb8 ffffffffa003abf6 ffffffff850e2ac0 8000000000000163 ffff8801850e2ac0 ffff8801850e2ac0 Call Trace: [] dump_stack+0x63/0x82 [] ubi_eba_read_leb+0x486/0x4a0 [ubi] [] ubi_check_volume+0x83/0xf0 [ubi] [] ubi_open_volume+0x177/0x350 [ubi] [] vol_cdev_open+0x58/0xb0 [ubi] [] chrdev_open+0xae/0x1d0 [] do_dentry_open+0x1ff/0x300 [] ? cdev_put+0x30/0x30 [] vfs_open+0x56/0x60 [] path_openat+0x4f4/0x1190 [] do_filp_open+0x91/0x100 [] ? __alloc_fd+0xc7/0x190 [] do_sys_open+0x13f/0x210 [] SyS_open+0x1e/0x20 [] entry_SYSCALL_64_fastpath+0x1a/0xa4 UBI checks static volumes for data consistency and reads the whole volume upon first open. If the volume is found erroneous users of UBI cannot read from it, but another volume update is possible to fix it. The check is performed by running ubi_eba_read_leb() on every allocated LEB of the volume. For static volumes ubi_eba_read_leb() computes the checksum of all data stored in a LEB. To verify the computed checksum it has to read the LEB's volume header which stores the original checksum. If the volume header is not found UBI treats this as fatal internal error and switches to RO mode. If the UBI device was attached via a full scan the assumption is correct, the volume header has to be present as it had to be there while scanning to get known as mapped. If the attach operation happened via Fastmap the assumption is no longer correct. When attaching via Fastmap UBI learns the mapping table from Fastmap's snapshot of the system state and not via a full scan. It can happen that a LEB got unmapped after a Fastmap was written to the flash. Then UBI can learn the LEB still as mapped and accessing it returns only 0xFF bytes. As UBI is not a FTL it is allowed to have mappings to empty PEBs, it assumes that the layer above takes care of LEB accounting and referencing. UBIFS does so using the LEB property tree (LPT). For static volumes UBI blindly assumes that all LEBs are present and therefore special actions have to be taken. The described situation can happen when updating a static volume is interrupted, either by a user or a power cut. The volume update code first unmaps all LEBs of a volume and then writes LEB by LEB. If the sequence of operations is interrupted UBI detects this either by the absence of LEBs, no volume header present at scan time, or corrupted payload, detected via checksum. In the Fastmap case the former method won't trigger as no scan happened and UBI automatically thinks all LEBs are present. Only by reading data from a LEB it detects that the volume header is missing and incorrectly treats this as fatal error. To deal with the situation ubi_eba_read_leb() from now on checks whether we attached via Fastmap and handles the absence of a volume header like a data corruption error. This way interrupted static volume updates will correctly get detected also when Fastmap is used. Cc: Reported-by: Ezequiel Garcia Tested-by: Ezequiel Garcia Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin

UBI: Fastmap: Calc fastmap size correctly

2014-10-03T14:33:28Z

We need to add fm_sb too. Signed-off-by: Richard Weinberger Reviewed-by: Tanya Brokhman Signed-off-by: Artem Bityutskiy

UBI: add missing kmem_cache_free() in process_pool_aeb error path

2014-09-16T15:18:58Z

I ran into this error after a ubiupdatevol, because I forgot to backport e9110361a9a4 UBI: fix the volumes tree sorting criteria. UBI error: process_pool_aeb: orphaned volume in fastmap pool UBI error: ubi_scan_fastmap: Attach by fastmap failed, doing a full scan! kmem_cache_destroy ubi_ainf_peb_slab: Slab cache still has objects CPU: 0 PID: 1 Comm: swapper Not tainted 3.14.18-00053-gf05cac8dbf85 #1 [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [] (show_stack) from [] (destroy_ai+0x230/0x244) [] (destroy_ai) from [] (ubi_attach+0x98/0x1ec) [] (ubi_attach) from [] (ubi_attach_mtd_dev+0x2b8/0x868) [] (ubi_attach_mtd_dev) from [] (ubi_init+0x1dc/0x2ac) [] (ubi_init) from [] (do_one_initcall+0x94/0x140) [] (do_one_initcall) from [] (kernel_init_freeable+0xe8/0x1b0) [] (kernel_init_freeable) from [] (kernel_init+0x8/0xe4) [] (kernel_init) from [] (ret_from_fork+0x14/0x24) UBI: scanning is finished Freeing the cache in the error path fixes the Slab error. Tested on at91sam9g35 (3.14.18+fastmap backports) Signed-off-by: Richard Genoud Cc: stable # 3.10+

UBI: fastmap: do not miss bit-flips

2014-07-16T05:32:00Z

The return value from 'ubi_io_read_ec_hdr()' was stored in 'err', not in 'ret'. This fix makes sure Fastmap-enabled UBI does not miss bit-flip while reading EC headers, events and scrubs the affected PEBs. This issue was reported by Coverity Scan. Artem: improved the commit message. Signed-off-by: Brian Norris Acked-by: Richard Weinberger Signed-off-by: Artem Bityutskiy

UBI: fix the volumes tree sorting criteria

2014-07-01T06:23:03Z

Commig "604b592 UBI: fix rb_tree node comparison in add_map" broke fastmap backward compatibility and older fastmap images cannot be mounted anymore. The reason is that it changes the volumes RB-tree sorting criteria. This patch fixes the problem. Artem: re-write the commit message Signed-off-by: Heiko Schocher Acked-by: Richard Weinberger Signed-off-by: Artem Bityutskiy

UBI: fix rb_tree node comparison in add_map

2014-05-13T10:47:23Z

The comparisons used in add_vol() shouldn't be identical. Pretty sure the following is correct but it is completely untested. Signed-off-by: Mike Snitzer Acked-by: Richard Weinberger Signed-off-by: Artem Bityutskiy

UBI: fix some use after free bugs

2014-02-04T07:44:30Z

Move the kmem_cache_free() calls down a couple lines. Signed-off-by: Dan Carpenter Signed-off-by: Artem Bityutskiy

UBI: Add some asserts to ubi_attach_fastmap()

2013-10-03T16:42:51Z

Add more paranioa asserts to make it easier to detect implementation errors. Signed-off-by: Richard Weinberger Signed-off-by: Artem Bityutskiy

UBI: Fix memory leak in ubi_attach_fastmap() error path

2013-10-03T16:42:50Z

On error we have to free all three temporary lists. Reported-by: Richard Genoud Signed-off-by: Richard Weinberger Signed-off-by: Artem Bityutskiy