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ubifs: ubifs_tnc_start_commit: Fix OOB in layout_in_gaps
[ Upstream commit 6abf572621
]
Running stress-test test_2 in mtd-utils on ubi device, sometimes we can
get following oops message:
BUG: unable to handle page fault for address: ffffffff00000140
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 280a067 P4D 280a067 PUD 0
Oops: 0000 [#1] SMP
CPU: 0 PID: 60 Comm: kworker/u16:1 Kdump: loaded Not tainted 5.2.0 #13
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0
-0-ga698c8995f-prebuilt.qemu.org 04/01/2014
Workqueue: writeback wb_workfn (flush-ubifs_0_0)
RIP: 0010:rb_next_postorder+0x2e/0xb0
Code: 80 db 03 01 48 85 ff 0f 84 97 00 00 00 48 8b 17 48 83 05 bc 80 db
03 01 48 83 e2 fc 0f 84 82 00 00 00 48 83 05 b2 80 db 03 01 <48> 3b 7a
10 48 89 d0 74 02 f3 c3 48 8b 52 08 48 83 05 a3 80 db 03
RSP: 0018:ffffc90000887758 EFLAGS: 00010202
RAX: ffff888129ae4700 RBX: ffff888138b08400 RCX: 0000000080800001
RDX: ffffffff00000130 RSI: 0000000080800024 RDI: ffff888138b08400
RBP: ffff888138b08400 R08: ffffea0004a6b920 R09: 0000000000000000
R10: ffffc90000887740 R11: 0000000000000001 R12: ffff888128d48000
R13: 0000000000000800 R14: 000000000000011e R15: 00000000000007c8
FS: 0000000000000000(0000) GS:ffff88813ba00000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffff00000140 CR3: 000000013789d000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
destroy_old_idx+0x5d/0xa0 [ubifs]
ubifs_tnc_start_commit+0x4fe/0x1380 [ubifs]
do_commit+0x3eb/0x830 [ubifs]
ubifs_run_commit+0xdc/0x1c0 [ubifs]
Above Oops are due to the slab-out-of-bounds happened in do-while of
function layout_in_gaps indirectly called by ubifs_tnc_start_commit. In
function layout_in_gaps, there is a do-while loop placing index nodes
into the gaps created by obsolete index nodes in non-empty index LEBs
until rest index nodes can totally be placed into pre-allocated empty
LEBs. @c->gap_lebs points to a memory area(integer array) which records
LEB numbers used by 'in-the-gaps' method. Whenever a fitable index LEB
is found, corresponding lnum will be incrementally written into the
memory area pointed by @c->gap_lebs. The size
((@c->lst.idx_lebs + 1) * sizeof(int)) of memory area is allocated before
do-while loop and can not be changed in the loop. But @c->lst.idx_lebs
could be increased by function ubifs_change_lp (called by
layout_leb_in_gaps->ubifs_find_dirty_idx_leb->get_idx_gc_leb) during the
loop. So, sometimes oob happens when number of cycles in do-while loop
exceeds the original value of @c->lst.idx_lebs. See detail in
https://bugzilla.kernel.org/show_bug.cgi?id=204229.
This patch fixes oob in layout_in_gaps.
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
parent
3900f9268a
commit
0c261ca281
1 changed files with 27 additions and 7 deletions
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@ -212,7 +212,7 @@ static int is_idx_node_in_use(struct ubifs_info *c, union ubifs_key *key,
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/**
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* layout_leb_in_gaps - layout index nodes using in-the-gaps method.
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* @c: UBIFS file-system description object
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* @p: return LEB number here
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* @p: return LEB number in @c->gap_lebs[p]
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*
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* This function lays out new index nodes for dirty znodes using in-the-gaps
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* method of TNC commit.
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@ -221,7 +221,7 @@ static int is_idx_node_in_use(struct ubifs_info *c, union ubifs_key *key,
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* This function returns the number of index nodes written into the gaps, or a
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* negative error code on failure.
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*/
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static int layout_leb_in_gaps(struct ubifs_info *c, int *p)
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static int layout_leb_in_gaps(struct ubifs_info *c, int p)
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{
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struct ubifs_scan_leb *sleb;
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struct ubifs_scan_node *snod;
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@ -236,7 +236,7 @@ static int layout_leb_in_gaps(struct ubifs_info *c, int *p)
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* filled, however we do not check there at present.
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*/
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return lnum; /* Error code */
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*p = lnum;
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c->gap_lebs[p] = lnum;
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dbg_gc("LEB %d", lnum);
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/*
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* Scan the index LEB. We use the generic scan for this even though
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@ -355,7 +355,7 @@ static int get_leb_cnt(struct ubifs_info *c, int cnt)
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*/
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static int layout_in_gaps(struct ubifs_info *c, int cnt)
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{
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int err, leb_needed_cnt, written, *p;
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int err, leb_needed_cnt, written, p = 0, old_idx_lebs, *gap_lebs;
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dbg_gc("%d znodes to write", cnt);
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@ -364,9 +364,9 @@ static int layout_in_gaps(struct ubifs_info *c, int cnt)
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if (!c->gap_lebs)
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return -ENOMEM;
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p = c->gap_lebs;
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old_idx_lebs = c->lst.idx_lebs;
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do {
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ubifs_assert(c, p < c->gap_lebs + c->lst.idx_lebs);
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ubifs_assert(c, p < c->lst.idx_lebs);
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written = layout_leb_in_gaps(c, p);
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if (written < 0) {
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err = written;
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@ -392,9 +392,29 @@ static int layout_in_gaps(struct ubifs_info *c, int cnt)
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leb_needed_cnt = get_leb_cnt(c, cnt);
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dbg_gc("%d znodes remaining, need %d LEBs, have %d", cnt,
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leb_needed_cnt, c->ileb_cnt);
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/*
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* Dynamically change the size of @c->gap_lebs to prevent
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* oob, because @c->lst.idx_lebs could be increased by
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* function @get_idx_gc_leb (called by layout_leb_in_gaps->
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* ubifs_find_dirty_idx_leb) during loop. Only enlarge
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* @c->gap_lebs when needed.
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*
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*/
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if (leb_needed_cnt > c->ileb_cnt && p >= old_idx_lebs &&
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old_idx_lebs < c->lst.idx_lebs) {
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old_idx_lebs = c->lst.idx_lebs;
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gap_lebs = krealloc(c->gap_lebs, sizeof(int) *
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(old_idx_lebs + 1), GFP_NOFS);
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if (!gap_lebs) {
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kfree(c->gap_lebs);
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c->gap_lebs = NULL;
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return -ENOMEM;
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}
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c->gap_lebs = gap_lebs;
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}
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} while (leb_needed_cnt > c->ileb_cnt);
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*p = -1;
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c->gap_lebs[p] = -1;
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return 0;
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}
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