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>
This commit is contained in:
Rabin Vincent
Richard Weinberger
parent
8326c1eec2
commit
8a1435880f
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@ -828,6 +828,24 @@ static int find_fm_anchor(struct ubi_attach_info *ai)
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return ret;
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}
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static struct ubi_ainf_peb *clone_aeb(struct ubi_attach_info *ai,
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struct ubi_ainf_peb *old)
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{
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struct ubi_ainf_peb *new;
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new = ubi_alloc_aeb(ai, old->pnum, old->ec);
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if (!new)
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return NULL;
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new->vol_id = old->vol_id;
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new->sqnum = old->sqnum;
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new->lnum = old->lnum;
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new->scrub = old->scrub;
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new->copy_flag = old->copy_flag;
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return new;
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}
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/**
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* ubi_scan_fastmap - scan the fastmap.
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* @ubi: UBI device object
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@ -847,7 +865,7 @@ int ubi_scan_fastmap(struct ubi_device *ubi, struct ubi_attach_info *ai,
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struct ubi_vid_hdr *vh;
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struct ubi_ec_hdr *ech;
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struct ubi_fastmap_layout *fm;
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struct ubi_ainf_peb *tmp_aeb, *aeb;
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struct ubi_ainf_peb *aeb;
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int i, used_blocks, pnum, fm_anchor, ret = 0;
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size_t fm_size;
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__be32 crc, tmp_crc;
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@ -857,9 +875,16 @@ int ubi_scan_fastmap(struct ubi_device *ubi, struct ubi_attach_info *ai,
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if (fm_anchor < 0)
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return UBI_NO_FASTMAP;
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/* Move all (possible) fastmap blocks into our new attach structure. */
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list_for_each_entry_safe(aeb, tmp_aeb, &scan_ai->fastmap, u.list)
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list_move_tail(&aeb->u.list, &ai->fastmap);
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/* Copy all (possible) fastmap blocks into our new attach structure. */
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list_for_each_entry(aeb, &scan_ai->fastmap, u.list) {
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struct ubi_ainf_peb *new;
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new = clone_aeb(ai, aeb);
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if (!new)
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return -ENOMEM;
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list_add(&new->u.list, &ai->fastmap);
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}
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down_write(&ubi->fm_protect);
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memset(ubi->fm_buf, 0, ubi->fm_size);
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