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From: Artem Labazov <123321artyom@gmail.com>
To: unlisted-recipients:; (no To-header on input)
Cc: 123321artyom@gmail.com, stable@vger.kernel.org,
	Namjae Jeon <namjae.jeon@samsung.com>,
	Sungjong Seo <sj1557.seo@samsung.com>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v3] exfat: Avoid allocating upcase table using kcalloc()
Date: Mon,  7 Dec 2020 12:34:23 +0300	[thread overview]
Message-ID: <20201207093424.833542-1-123321artyom@gmail.com> (raw)
In-Reply-To: <40be01d6cc61$7d23cac0$776b6040$@samsung.com>

The table for Unicode upcase conversion requires an order-5 allocation,
which may fail on a highly-fragmented system:

 pool-udisksd: page allocation failure: order:5, mode:0x40dc0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO), nodemask=(null),cpuset=/,mems_allowed=0
 CPU: 4 PID: 3756880 Comm: pool-udisksd Tainted: G     U            5.8.10-200.fc32.x86_64 #1
 Hardware name: Dell Inc. XPS 13 9360/0PVG6D, BIOS 2.13.0 11/14/2019
 Call Trace:
  dump_stack+0x6b/0x88
  warn_alloc.cold+0x75/0xd9
  ? _cond_resched+0x16/0x40
  ? __alloc_pages_direct_compact+0x144/0x150
  __alloc_pages_slowpath.constprop.0+0xcfa/0xd30
  ? __schedule+0x28a/0x840
  ? __wait_on_bit_lock+0x92/0xa0
  __alloc_pages_nodemask+0x2df/0x320
  kmalloc_order+0x1b/0x80
  kmalloc_order_trace+0x1d/0xa0
  exfat_create_upcase_table+0x115/0x390 [exfat]
  exfat_fill_super+0x3ef/0x7f0 [exfat]
  ? sget_fc+0x1d0/0x240
  ? exfat_init_fs_context+0x120/0x120 [exfat]
  get_tree_bdev+0x15c/0x250
  vfs_get_tree+0x25/0xb0
  do_mount+0x7c3/0xaf0
  ? copy_mount_options+0xab/0x180
  __x64_sys_mount+0x8e/0xd0
  do_syscall_64+0x4d/0x90
  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Convert kcalloc/kfree to their kv* variants to eliminate the issue.

Cc: stable@vger.kernel.org # v5.7+
Signed-off-by: Artem Labazov <123321artyom@gmail.com>
---
v2: replace vmalloc with vzalloc to avoid uninitialized memory access
v3: use kv* functions to attempt kmalloc first

 fs/exfat/nls.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/exfat/nls.c b/fs/exfat/nls.c
index 675d0e7058c5..314d5407a1be 100644
--- a/fs/exfat/nls.c
+++ b/fs/exfat/nls.c
@@ -659,7 +659,7 @@ static int exfat_load_upcase_table(struct super_block *sb,
 	unsigned char skip = false;
 	unsigned short *upcase_table;
 
-	upcase_table = kcalloc(UTBL_COUNT, sizeof(unsigned short), GFP_KERNEL);
+	upcase_table = kvcalloc(UTBL_COUNT, sizeof(unsigned short), GFP_KERNEL);
 	if (!upcase_table)
 		return -ENOMEM;
 
@@ -715,7 +715,7 @@ static int exfat_load_default_upcase_table(struct super_block *sb)
 	unsigned short uni = 0, *upcase_table;
 	unsigned int index = 0;
 
-	upcase_table = kcalloc(UTBL_COUNT, sizeof(unsigned short), GFP_KERNEL);
+	upcase_table = kvcalloc(UTBL_COUNT, sizeof(unsigned short), GFP_KERNEL);
 	if (!upcase_table)
 		return -ENOMEM;
 
@@ -803,5 +803,5 @@ int exfat_create_upcase_table(struct super_block *sb)
 
 void exfat_free_upcase_table(struct exfat_sb_info *sbi)
 {
-	kfree(sbi->vol_utbl);
+	kvfree(sbi->vol_utbl);
 }
-- 
2.26.2


  reply	other threads:[~2020-12-07  9:38 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20201124194858epcas1p49cacda6a9b4877ff125f25f4dc5fcadf@epcas1p4.samsung.com>
2020-11-24 19:47 ` [PATCH] exfat: Avoid allocating upcase table using kcalloc() Artem Labazov
2020-11-24 22:17   ` David Laight
2020-12-02  4:58   ` Sungjong Seo
2020-12-04 12:57     ` Artem Labazov
2020-12-07  6:23       ` Sungjong Seo
2020-12-07  9:34         ` Artem Labazov [this message]
2020-12-08  2:22           ` [PATCH v3] " Sungjong Seo
2020-12-04 13:33     ` [PATCH v2] " Artem Labazov
2020-12-07  4:32       ` Namjae Jeon

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