pm24.git/drivers/mtd/ubi, branch rust-6.8

ubi: block: Fix use-after-free in ubiblock_cleanup

2023-10-28T21:18:39Z

The following BUG is reported when a ubiblock is removed: ================================================================== BUG: KASAN: slab-use-after-free in ubiblock_cleanup+0x88/0xa0 [ubi] Read of size 4 at addr ffff88810c8f3804 by task ubiblock/1716 CPU: 5 PID: 1716 Comm: ubiblock Not tainted 6.6.0-rc2+ #135 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014 Call Trace: dump_stack_lvl+0x37/0x50 print_report+0xd0/0x620 kasan_report+0xb6/0xf0 ubiblock_cleanup+0x88/0xa0 [ubi] ubiblock_remove+0x121/0x190 [ubi] vol_cdev_ioctl+0x355/0x630 [ubi] __x64_sys_ioctl+0xc7/0x100 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 RIP: 0033:0x7f08d7445577 Code: b3 66 90 48 8b 05 11 89 2c 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e1 8 RSP: 002b:00007ffde05a3018 EFLAGS: 00000206 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 00007f08d7445577 RDX: 0000000000000000 RSI: 0000000000004f08 RDI: 0000000000000003 RBP: 0000000000816010 R08: 00000000008163a7 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000206 R12: 0000000000000003 R13: 00007ffde05a3130 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 1715: kasan_save_stack+0x22/0x50 kasan_set_track+0x25/0x30 __kasan_kmalloc+0x7f/0x90 __alloc_disk_node+0x40/0x2b0 __blk_mq_alloc_disk+0x3e/0xb0 ubiblock_create+0x2ba/0x620 [ubi] vol_cdev_ioctl+0x581/0x630 [ubi] __x64_sys_ioctl+0xc7/0x100 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 Freed by task 0: kasan_save_stack+0x22/0x50 kasan_set_track+0x25/0x30 kasan_save_free_info+0x2b/0x50 __kasan_slab_free+0x10e/0x190 __kmem_cache_free+0x96/0x220 bdev_free_inode+0xa4/0xf0 rcu_core+0x496/0xec0 __do_softirq+0xeb/0x384 The buggy address belongs to the object at ffff88810c8f3800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 4 bytes inside of freed 1024-byte region [ffff88810c8f3800, ffff88810c8f3c00) The buggy address belongs to the physical page: page:00000000d03de848 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10c8f0 head:00000000d03de848 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x200000000000840(slab|head|node=0|zone=2) page_type: 0xffffffff() raw: 0200000000000840 ffff888100042dc0 ffffea0004244400 dead000000000002 raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88810c8f3700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88810c8f3780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88810c8f3800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88810c8f3880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88810c8f3900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Fix it by using a local variable to record the gendisk ID. Fixes: 77567b25ab9f ("ubi: use blk_mq_alloc_disk and blk_cleanup_disk") Signed-off-by: ZhaoLong Wang Reviewed-by: Zhihao Cheng Signed-off-by: Richard Weinberger

ubi: fastmap: Add control in 'UBI_IOCATT' ioctl to reserve PEBs for filling pools

2023-10-28T21:16:00Z

This patch imports a new field 'need_resv_pool' in struct 'ubi_attach_req' to control whether or not reserving free PEBs for filling pool/wl_pool. Link: https://bugzilla.kernel.org/show_bug.cgi?id=217787 Signed-off-by: Zhihao Cheng Signed-off-by: Richard Weinberger

ubi: fastmap: Add module parameter to control reserving filling pool PEBs

2023-10-28T21:15:44Z

Adding 6th module parameter in 'mtd=xxx' to control whether or not reserving PEBs for filling pool/wl_pool. Signed-off-by: Zhihao Cheng Signed-off-by: Richard Weinberger

ubi: fastmap: Fix lapsed wear leveling for first 64 PEBs

2023-10-28T21:14:55Z

The anchor PEB must be picked from first 64 PEBs, these PEBs could have large erase counter greater than other PEBs especially when free space is nearly running out. The ubi_update_fastmap will be called as long as pool/wl_pool is empty, old anchor PEB is erased when updating fastmap. Given an UBI device with N PEBs, free PEBs is nearly running out and pool will be filled with 1 PEB every time ubi_update_fastmap invoked. So t=N/POOL_SIZE[1]/64 means that in worst case the erase counter of first 64 PEBs is t times greater than other PEBs in theory. After running fsstress for 24h, the erase counter statistics for two UBI devices shown as follow(CONFIG_MTD_UBI_WL_THRESHOLD=128): Device A(1024 PEBs, pool=50, wl_pool=25): ========================================================= from to count min avg max --------------------------------------------------------- 0 .. 9: 0 0 0 0 10 .. 99: 0 0 0 0 100 .. 999: 0 0 0 0 1000 .. 9999: 0 0 0 0 10000 .. 99999: 960 29224 29282 29362 100000 .. inf: 64 117897 117934 117940 --------------------------------------------------------- Total : 1024 29224 34822 117940 Device B(8192 PEBs, pool=256, wl_pool=128): ========================================================= from to count min avg max --------------------------------------------------------- 0 .. 9: 0 0 0 0 10 .. 99: 0 0 0 0 100 .. 999: 0 0 0 0 1000 .. 9999: 8128 2253 2321 2387 10000 .. 99999: 64 35387 35387 35388 100000 .. inf: 0 0 0 0 --------------------------------------------------------- Total : 8192 2253 2579 35388 The key point is reducing fastmap updating frequency by enlarging POOL_SIZE, so let UBI reserve ubi->fm_pool.max_size PEBs during attaching. Then POOL_SIZE will become ubi->fm_pool.max_size/2 even in free space running out case. Given an UBI device with 8192 PEBs(16384\8192\4096 is common large-capacity flash), t=8192/128/64=1. The fastmap updating will happen in either wl_pool or pool is empty, so setting fm_pool_rsv_cnt as ubi->fm_pool.max_size can fill wl_pool in full state. After pool reservation, running fsstress for 24h: Device A(1024 PEBs, pool=50, wl_pool=25): ========================================================= from to count min avg max --------------------------------------------------------- 0 .. 9: 0 0 0 0 10 .. 99: 0 0 0 0 100 .. 999: 0 0 0 0 1000 .. 9999: 0 0 0 0 10000 .. 99999: 1024 33801 33997 34056 100000 .. inf: 0 0 0 0 --------------------------------------------------------- Total : 1024 33801 33997 34056 Device B(8192 PEBs, pool=256, wl_pool=128): ========================================================= from to count min avg max --------------------------------------------------------- 0 .. 9: 0 0 0 0 10 .. 99: 0 0 0 0 100 .. 999: 0 0 0 0 1000 .. 9999: 8192 2205 2397 2460 10000 .. 99999: 0 0 0 0 100000 .. inf: 0 0 0 0 --------------------------------------------------------- Total : 8192 2205 2397 2460 The difference of erase counter between first 64 PEBs and others is under WL_FREE_MAX_DIFF(2*UBI_WL_THRESHOLD=2*128=256). Device A: 34056 - 33801 = 255 Device B: 2460 - 2205 = 255 Next patch will add a switch to control whether UBI needs to reserve PEBs for filling pool. Fixes: dbb7d2a88d2a ("UBI: Add fastmap core") Link: https://bugzilla.kernel.org/show_bug.cgi?id=217787 Signed-off-by: Zhihao Cheng Signed-off-by: Richard Weinberger

ubi: fastmap: Get wl PEB even ec beyonds the 'max' if free PEBs are run out

2023-10-28T21:07:54Z

This is the part 2 to fix cyclically reusing single fastmap data PEBs. Consider one situation, if there are four free PEBs for fm_anchor, pool, wl_pool and fastmap data PEB with erase counter 100, 100, 100, 5096 (ubi->beb_rsvd_pebs is 0). PEB with erase counter 5096 is always picked for fastmap data according to the realization of find_wl_entry(), since fastmap data PEB is not scheduled for wl, finally there are two PEBs (fm data) with great erase counter than other PEBS. Get wl PEB even its erase counter exceeds the 'max' in find_wl_entry() when free PEBs are run out after filling pools and fm data. Then the PEB with biggest erase conter is taken as wl PEB, it can be scheduled for wl. Fixes: dbb7d2a88d2a ("UBI: Add fastmap core") Link: https://bugzilla.kernel.org/show_bug.cgi?id=217787 Signed-off-by: Zhihao Cheng Signed-off-by: Richard Weinberger

ubi: fastmap: may_reserve_for_fm: Don't reserve PEB if fm_anchor exists

2023-10-28T20:49:14Z

This is the part 1 to fix cyclically reusing single fastmap data PEBs. After running fsstress on UBIFS for a while, UBI (16384 blocks, fastmap takes 2 blocks) has an erase block(PEB: 8031) with big erase counter greater than any other pebs: ========================================================= from to count min avg max --------------------------------------------------------- 0 .. 9: 0 0 0 0 10 .. 99: 532 84 92 99 100 .. 999: 15787 100 147 229 1000 .. 9999: 64 4699 4765 4826 10000 .. 99999: 0 0 0 0 100000 .. inf: 1 272935 272935 272935 --------------------------------------------------------- Total : 16384 84 180 272935 Not like fm_anchor, there is no candidate PEBs for fastmap data area, so old fastmap data pebs will be reused after all free pebs are filled into pool/wl_pool: ubi_update_fastmap for (i = 1; i < new_fm->used_blocks; i++) erase_block(ubi, old_fm->e[i]->pnum) new_fm->e[i] = old_fm->e[i] According to wear leveling algorithm, UBI selects one small erase counter PEB from ubi->used and one big erase counter PEB from wl_pool, the reused fastmap data PEB is not in these trees. UBI won't schedule this PEB for wl even it is in ubi->used because wl algorithm expects small erase counter for used PEB. Don't reserve PEB for fastmap in may_reserve_for_fm() if fm_anchor already exists. Otherwise, when UBI is running out of free PEBs, the only one free PEB (pnum < 64) will be skipped and fastmap data will be written on the same old PEB. Fixes: dbb7d2a88d2a ("UBI: Add fastmap core") Link: https://bugzilla.kernel.org/show_bug.cgi?id=217787 Signed-off-by: Zhihao Cheng Signed-off-by: Richard Weinberger

ubi: fastmap: Remove unneeded break condition while filling pools

2023-10-28T20:47:43Z

Change pool filling stop condition. Commit d09e9a2bddba ("ubi: fastmap: Fix high cpu usage of ubi_bgt by making sure wl_pool not empty") reserves fastmap data PEBs after filling 1 PEB in wl_pool. Now wait_free_pebs_for_pool() makes enough free PEBs before filling pool, there will still be at least 1 PEB in pool and 1 PEB in wl_pool after doing ubi_refill_pools(). Signed-off-by: Zhihao Cheng Signed-off-by: Richard Weinberger

ubi: fastmap: Wait until there are enough free PEBs before filling pools

2023-10-28T20:43:40Z

Wait until there are enough free PEBs before filling pool/wl_pool, sometimes erase_worker is not scheduled in time, which causes two situations: A. There are few PEBs filled in pool, which makes ubi_update_fastmap is frequently called and leads first 64 PEBs are erased more times than other PEBs. So waiting free PEBs before filling pool reduces fastmap updating frequency and prolongs flash service life. B. In situation that space is nearly running out, ubi_refill_pools() cannot make sure pool and wl_pool are filled with free PEBs, caused by the delay of erase_worker. After this patch applied, there must exist free PEBs in pool after one call of ubi_update_fastmap. Besides, this patch is a preparetion for fixing large erase counter in fastmap data block and fixing lapsed wear leveling for first 64 PEBs. Link: https://bugzilla.kernel.org/show_bug.cgi?id=217787 Signed-off-by: Zhihao Cheng Signed-off-by: Richard Weinberger

ubi: fastmap: Use free pebs reserved for bad block handling

2023-10-28T20:41:01Z

If new bad PEBs occur, UBI firstly consumes ubi->beb_rsvd_pebs, and then ubi->avail_pebs, finally UBI becomes read-only if above two items are 0, which means that the amount of PEBs for user volumes is not effected. Besides, UBI reserves count of free PBEs is ubi->beb_rsvd_pebs while filling wl pool or getting free PEBs, but ubi->avail_pebs is not reserved. So ubi->beb_rsvd_pebs and ubi->avail_pebs have nothing to do with the usage of free PEBs, UBI can use all free PEBs. Commit 78d6d497a648 ("UBI: Move fastmap specific functions out of wl.c") has removed beb_rsvd_pebs checking while filling pool. Now, don't reserve ubi->beb_rsvd_pebs while filling wl_pool. This will fill more PEBs in pool and also reduce fastmap updating frequency. Also remove beb_rsvd_pebs checking in ubi_wl_get_fm_peb. Link: https://bugzilla.kernel.org/show_bug.cgi?id=217787 Signed-off-by: Zhihao Cheng Signed-off-by: Richard Weinberger

ubi: Replace erase_block() with sync_erase()

2023-10-28T20:34:24Z

Since erase_block() has same logic with sync_erase(), just replace it with sync_erase(), also rename 'sync_erase()' to 'ubi_sync_erase()'. Signed-off-by: Zhihao Cheng Signed-off-by: Richard Weinberger