From: Ruslan Bilovol <ruslan.bilovol@ti.com>
To: tytso@mit.edu, adilger.kernel@dilger.ca
Cc: linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] jbd2: check bh->b_data for NULL in jbd2_journal_get_descriptor_buffer before memset()
Date: Mon, 3 Jun 2013 13:00:15 +0300 [thread overview]
Message-ID: <1370253616-8173-2-git-send-email-ruslan.bilovol@ti.com> (raw)
In-Reply-To: <1370253616-8173-1-git-send-email-ruslan.bilovol@ti.com>
The memset() doesn't perform any NULL-pointer checking
before dereferencing passed pointer so this should be
checked before calling it.
This fixes next issue:
[38200.069122] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[38200.078002] pgd = c0004000
[38200.080963] [00000000] *pgd=00000000
[38200.084991] Internal error: Oops: 805 [#1] PREEMPT SMP ARM
[38200.091003] Modules linked in: rproc_drm(O) tf_driver(O) gps_drv wl18xx(O) wl12xx(O) wlcore(O) mac80211(O) cfg80211(O) pvrsrvkm_sgx540_120(O) compat(O)
[38200.106719] CPU: 1 Tainted: G W O (3.4.34 #1)
[38200.112579] PC is at __memzero+0x24/0x80
[38200.116882] LR is at 0x0
[38200.119689] pc : [<c023b004>] lr : [<00000000>] psr: 28000113
[38200.119689] sp : d66b1e2c ip : 00000000 fp : d66b1e54
[38200.132171] r10: 00000000 r9 : d6ad48c0 r8 : c01bd414
[38200.137847] r7 : 00000000 r6 : ffffffff r5 : cb19fe48 r4 : d678bc00
[38200.144958] r3 : 00000000 r2 : 00000000 r1 : 00000fc0 r0 : 00000000
[38200.152008] Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel
[38200.160034] Control: 10c5387d Table: 967b004a DAC: 00000015
[...]
[38200.888031] Backtrace:
[38200.890869] [<c01c509c>] (jbd2_journal_get_descriptor_buffer+0x0/0xa4) from [<c01bddf0>] (jbd2_journal_commit_transaction+0x994/0x18f4)
[38200.903930] r5:d6ad5348 r4:d678bc00
[38200.907989] [<c01bd45c>] (jbd2_journal_commit_transaction+0x0/0x18f4) from [<c01c2e70>] (kjournald2+0xb4/0x24c)
[38200.918884] [<c01c2dbc>] (kjournald2+0x0/0x24c) from [<c0066990>] (kthread+0x90/0x9c)
[38200.927429] [<c0066900>] (kthread+0x0/0x9c) from [<c004a968>] (do_exit+0x0/0x804)
[38200.935577] r6:c004a968 r5:c0066900 r4:d6749c8c
[38200.940887] Code: e52de004 e1a0c002 e1a0e002 e2511040 (a8a0500c)
Signed-off-by: Ruslan Bilovol <ruslan.bilovol@ti.com>
---
fs/jbd2/journal.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 9545757..48f3da5 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -810,7 +810,7 @@ struct journal_head *jbd2_journal_get_descriptor_buffer(journal_t *journal)
return NULL;
bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
- if (!bh)
+ if (!bh || !bh->b_data)
return NULL;
lock_buffer(bh);
memset(bh->b_data, 0, journal->j_blocksize);
--
1.7.9.5
next prev parent reply other threads:[~2013-06-03 10:00 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-03 10:00 [PATCH 0/2] Misc ext4 fixes Ruslan Bilovol
2013-06-03 10:00 ` Ruslan Bilovol [this message]
2013-06-03 15:33 ` [PATCH 1/2] jbd2: check bh->b_data for NULL in jbd2_journal_get_descriptor_buffer before memset() Theodore Ts'o
2013-06-04 11:15 ` Ruslan Bilovol
2013-06-04 13:37 ` Theodore Ts'o
2013-06-06 8:02 ` Ruslan Bilovol
2013-06-03 10:00 ` [PATCH 2/2] ext4: add sanity checks in __ext4_check_dir_entry Ruslan Bilovol
2013-06-03 15:40 ` Theodore Ts'o
2013-06-04 11:17 ` Ruslan Bilovol
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