kernel/linux.git/drivers/mtd/ubi, branch v3.18.62

ubi/upd: Always flush after prepared for an update

2017-04-30T03:49:13+00:00

commit 9cd9a21ce070be8a918ffd3381468315a7a76ba6 upstream. In commit 6afaf8a484cb ("UBI: flush wl before clearing update marker") I managed to trigger and fix a similar bug. Now here is another version of which I assumed it wouldn't matter back then but it turns out UBI has a check for it and will error out like this: |ubi0 warning: validate_vid_hdr: inconsistent used_ebs |ubi0 error: validate_vid_hdr: inconsistent VID header at PEB 592 All you need to trigger this is? "ubiupdatevol /dev/ubi0_0 file" + a powercut in the middle of the operation. ubi_start_update() sets the update-marker and puts all EBs on the erase list. After that userland can proceed to write new data while the old EB aren't erased completely. A powercut at this point is usually not that much of a tragedy. UBI won't give read access to the static volume because it has the update marker. It will most likely set the corrupted flag because it misses some EBs. So we are all good. Unless the size of the image that has been written differs from the old image in the magnitude of at least one EB. In that case UBI will find two different values for `used_ebs' and refuse to attach the image with the error message mentioned above. So in order not to get in the situation, the patch will ensure that we wait until everything is removed before it tries to write any data. The alternative would be to detect such a case and remove all EBs at the attached time after we processed the volume-table and see the update-marker set. The patch looks bigger and I doubt it is worth it since usually the write() will wait from time to time for a new EB since usually there not that many spare EB that can be used. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Richard Weinberger Signed-off-by: Greg Kroah-Hartman

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

2017-04-18T05:55:45+00:00

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: Make volume resize power cut aware

2016-08-22T16:23:24+00:00

[ Upstream commit 4946784bd3924b1374f05eebff2fd68660bae866 ] When the volume resize operation shrinks a volume, LEBs will be unmapped. Since unmapping will not erase these LEBs immediately we have to wait for that operation to finish. Otherwise in case of a power cut right after writing the new volume table the UBI attach process can find more LEBs than the volume table knows. This will render the UBI image unattachable. Fix this issue by waiting for erase to complete and write the new volume table afterward. Cc: Reported-by: Boris Brezillon Reviewed-by: Boris Brezillon Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin

ubi: Fix race condition between ubi device creation and udev

2016-08-22T16:23:23+00:00

[ Upstream commit 714fb87e8bc05ff78255afc0dca981e8c5242785 ] Install the UBI device object before we arm sysfs. Otherwise udev tries to read sysfs attributes before UBI is ready and udev rules will not match. Cc: Signed-off-by: Iosif Harutyunov [rw: massaged commit message] Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin

UBI: Fastmap: Fix race in ubi_eba_atomic_leb_change()

2016-07-12T12:46:59+00:00

[ Upstream commit 36a87e44f642966442fd0d23f2ec536851e00236 ] This function a) requests a new PEB, b) writes data to it, c) returns the old PEB and d) registers the new PEB in the EBA table. For the non-fastmap case this works perfectly fine and is powercut safe. Is fastmap enabled this can lead to issues. If a new fastmap is written between a) and c) the freshly requested PEB is no longer in a pool and will not be scanned upon attaching. If now a powercut happens between c) and d) the freshly requested PEB will not be scanned and the old one got already scheduled for erase. After attaching the EBA table will point to a erased PEB. Fix this issue by swapping steps c) and d). Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin

UBI: Fix static volume checks when Fastmap is used

2016-06-06T23:11:13+00:00

[ 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: fix missing brace control flow

2016-06-06T23:11:13+00:00

[ Upstream commit b388e6a7a6ba988998ddd83919ae8d3debf1a13d ] commit 0e707ae79ba3 ("UBI: do propagate positive error codes up") seems to have produced an unintended change in the control flow here. Completely untested, but it looks obvious. Caught by Coverity, which didn't like the indentation. CID 1271184. Signed-off-by: Brian Norris Cc: Dan Carpenter Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin

UBI: do propagate positive error codes up

2016-06-06T23:11:13+00:00

[ Upstream commit 0e707ae79ba357d60b8a36025ec8968e5020d827 ] UBI uses positive function return codes internally, and should not propagate them up, except in the place this path fixes. Here is the original bug report from Dan Carpenter: The problem is really in ubi_eba_read_leb(). drivers/mtd/ubi/eba.c 412 err = ubi_io_read_vid_hdr(ubi, pnum, vid_hdr, 1); 413 if (err && err != UBI_IO_BITFLIPS) { 414 if (err > 0) { 415 /* 416 * The header is either absent or corrupted. 417 * The former case means there is a bug - 418 * switch to read-only mode just in case. 419 * The latter case means a real corruption - we 420 * may try to recover data. FIXME: but this is 421 * not implemented. 422 */ 423 if (err == UBI_IO_BAD_HDR_EBADMSG || 424 err == UBI_IO_BAD_HDR) { 425 ubi_warn("corrupted VID header at PEB %d, LEB %d:%d", 426 pnum, vol_id, lnum); 427 err = -EBADMSG; 428 } else 429 ubi_ro_mode(ubi); On this path we return UBI_IO_FF and UBI_IO_FF_BITFLIPS and it eventually gets passed to ERR_PTR(). We probably dereference the bad pointer and oops. At that point we've gone read only so it was already a bad situation... 430 } 431 goto out_free; 432 } else if (err == UBI_IO_BITFLIPS) 433 scrub = 1; 434 Reported-by: Dan Carpenter Signed-off-by: Artem Bityutskiy Signed-off-by: Sasha Levin

UBI: Fastmap: Ensure that only one fastmap work is scheduled

2016-06-06T23:11:12+00:00

[ Upstream commit 19371d73c9bd31a8e634ec5a80fc19fcd7714481 ] If the WL pool runs out of PEBs we schedule a fastmap write to refill it as soon as possible. Ensure that only one at a time is scheduled otherwise we might end in a fastmap write storm because writing the fastmap can schedule another write if bitflips are detected. Signed-off-by: Richard Weinberger Reviewed-by: Tanya Brokhman Reviewed-by: Guido Martínez Signed-off-by: Sasha Levin

ubi: Fix out of bounds write in volume update code

2016-03-13T17:53:41+00:00

[ Upstream commit e4f6daac20332448529b11f09388f1d55ef2084c ] ubi_start_leb_change() allocates too few bytes. ubi_more_leb_change_data() will write up to req->upd_bytes + ubi->min_io_size bytes. Cc: stable@vger.kernel.org Signed-off-by: Richard Weinberger Reviewed-by: Boris Brezillon Signed-off-by: Sasha Levin