LinuxPPC-Dev Archive on lore.kernel.org
 help / color / Atom feed
From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
To: Qiang Zhao <qiang.zhao@nxp.com>, Li Yang <leoyang.li@nxp.com>,
	Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Scott Wood <oss@buserror.net>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v4 38/47] soc: fsl: qe: refactor cpm_muram_alloc_common to prevent BUG on error path
Date: Fri,  8 Nov 2019 14:01:14 +0100
Message-ID: <20191108130123.6839-39-linux@rasmusvillemoes.dk> (raw)
In-Reply-To: <20191108130123.6839-1-linux@rasmusvillemoes.dk>

If the kmalloc() fails, we try to undo the gen_pool allocation we've
just done. Unfortunately, start has already been modified to subtract
the GENPOOL_OFFSET bias, so we're freeing something that very likely
doesn't exist in the gen_pool, meaning we hit the

 kernel BUG at lib/genalloc.c:399!
 Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
 ...
 [<803fd0e8>] (gen_pool_free) from [<80426bc8>] (cpm_muram_alloc_common+0xb0/0xc8)
 [<80426bc8>] (cpm_muram_alloc_common) from [<80426c28>] (cpm_muram_alloc+0x48/0x80)
 [<80426c28>] (cpm_muram_alloc) from [<80428214>] (ucc_slow_init+0x110/0x4f0)
 [<80428214>] (ucc_slow_init) from [<8044a718>] (qe_uart_request_port+0x3c/0x1d8)

(this was tested by just injecting a random failure by adding
"|| (get_random_int()&7) == 0" to the "if (!entry)" condition).

Refactor the code so we do the kmalloc() first, meaning that's the
thing that needs undoing in case gen_pool_alloc_algo() then
fails. This allows a later cleanup to move the locking from the
callers into the _common function, keeping the kmalloc() out of the
critical region and then, hopefully (if all the muram_alloc callers
allow) change it to a GFP_KERNEL allocation.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
 drivers/soc/fsl/qe/qe_common.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/drivers/soc/fsl/qe/qe_common.c b/drivers/soc/fsl/qe/qe_common.c
index feb33ec1c3d6..bc9b436684df 100644
--- a/drivers/soc/fsl/qe/qe_common.c
+++ b/drivers/soc/fsl/qe/qe_common.c
@@ -119,23 +119,21 @@ static s32 cpm_muram_alloc_common(unsigned long size,
 	struct muram_block *entry;
 	s32 start;
 
+	entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
+	if (!entry)
+		return -ENOMEM;
 	start = gen_pool_alloc_algo(muram_pool, size, algo, data);
-	if (!start)
-		goto out2;
+	if (!start) {
+		kfree(entry);
+		return -ENOMEM;
+	}
 	start = start - GENPOOL_OFFSET;
 	memset_io(cpm_muram_addr(start), 0, size);
-	entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
-	if (!entry)
-		goto out1;
 	entry->start = start;
 	entry->size = size;
 	list_add(&entry->head, &muram_block_list);
 
 	return start;
-out1:
-	gen_pool_free(muram_pool, start, size);
-out2:
-	return -ENOMEM;
 }
 
 /*
-- 
2.23.0


  parent reply index

Thread overview: 80+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-08 13:00 [PATCH v4 00/47] QUICC Engine support on ARM and ARM64 Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 01/47] soc: fsl: qe: remove space-before-tab Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 02/47] soc: fsl: qe: drop volatile qualifier of struct qe_ic::regs Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 03/47] soc: fsl: qe: rename qe_(clr/set/clrset)bit* helpers Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 04/47] soc: fsl: qe: introduce qe_io{read,write}* wrappers Rasmus Villemoes
2019-11-12  5:17   ` [PATCH v4 04/47] soc: fsl: qe: introduce qe_io{read, write}* wrappers Timur Tabi
2019-11-12  7:14     ` [PATCH v4 04/47] soc: fsl: qe: introduce qe_io{read,write}* wrappers Rasmus Villemoes
2019-11-14  5:08       ` Timur Tabi
2019-11-14  8:55         ` Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 05/47] soc: fsl: qe: avoid ppc-specific io accessors Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 06/47] soc: fsl: qe: replace spin_event_timeout by readx_poll_timeout_atomic Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 07/47] soc: fsl: qe: qe.c: guard use of pvr_version_is() with CONFIG_PPC32 Rasmus Villemoes
2019-11-15  4:50   ` Timur Tabi
2019-11-15  8:11     ` Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 08/47] soc: fsl: qe: drop unneeded #includes Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 09/47] soc: fsl: qe: drop assign-only high_active in qe_ic_init Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 10/47] soc: fsl: qe: remove pointless sysfs registration in qe_ic.c Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 11/47] soc: fsl: qe: use qe_ic_cascade_{low, high}_mpic also on 83xx Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 12/47] soc: fsl: qe: move calls of qe_ic_init out of arch/powerpc/ Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 13/47] powerpc/83xx: remove mpc83xx_ipic_and_qe_init_IRQ Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 14/47] powerpc/85xx: remove mostly pointless mpc85xx_qe_init() Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 15/47] soc: fsl: qe: move qe_ic_cascade_* functions to qe_ic.c Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 16/47] soc: fsl: qe: rename qe_ic_cascade_low_mpic -> qe_ic_cascade_low Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 17/47] soc: fsl: qe: remove unused qe_ic_set_* functions Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 18/47] soc: fsl: qe: don't use NO_IRQ in qe_ic.c Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 19/47] soc: fsl: qe: make qe_ic_get_{low,high}_irq static Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 20/47] soc: fsl: qe: simplify qe_ic_init() Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 21/47] soc: fsl: qe: merge qe_ic.h headers into qe_ic.c Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 22/47] soc: fsl: qe: qe.c: use of_property_read_* helpers Rasmus Villemoes
2019-11-08 13:00 ` [PATCH v4 23/47] soc: fsl: qe: qe_io.c: don't open-code of_parse_phandle() Rasmus Villemoes
2019-11-08 13:01 ` [PATCH v4 24/47] soc: fsl: qe: qe_io.c: access device tree property using be32_to_cpu Rasmus Villemoes
2019-11-08 13:01 ` [PATCH v4 25/47] soc: fsl: qe: qe_io.c: use of_property_read_u32() in par_io_init() Rasmus Villemoes
2019-11-08 13:01 ` [PATCH v4 26/47] soc: fsl: move cpm.h from powerpc/include/asm to include/soc/fsl Rasmus Villemoes
2019-11-08 13:01 ` [PATCH v4 27/47] soc/fsl/qe/qe.h: update include path for cpm.h Rasmus Villemoes
2019-11-08 13:01 ` [PATCH v4 28/47] serial: ucc_uart: explicitly include soc/fsl/cpm.h Rasmus Villemoes
2019-11-08 13:01 ` [PATCH v4 29/47] serial: ucc_uart: replace ppc-specific IO accessors Rasmus Villemoes
2019-11-08 13:01 ` [PATCH v4 30/47] serial: ucc_uart: factor out soft_uart initialization Rasmus Villemoes
2019-11-14  5:14   ` Timur Tabi
2019-11-14  9:00     ` Rasmus Villemoes
2019-11-08 13:01 ` [PATCH v4 31/47] serial: ucc_uart: stub out soft_uart_init for !CONFIG_PPC32 Rasmus Villemoes
2019-11-08 13:01 ` [PATCH v4 32/47] serial: ucc_uart: use of_property_read_u32() in ucc_uart_probe() Rasmus Villemoes
2019-11-14 13:57   ` Timur Tabi
2019-11-15  8:01     ` Rasmus Villemoes
2019-11-15 14:35       ` Timur Tabi
2019-11-15 22:44         ` Scott Wood
2019-11-15  4:25   ` Timur Tabi
2019-11-15  7:57     ` Rasmus Villemoes
2019-11-08 13:01 ` [PATCH v4 33/47] serial: ucc_uart: access __be32 field using be32_to_cpu Rasmus Villemoes
2019-11-08 13:01 ` [PATCH v4 34/47] soc: fsl: qe: change return type of cpm_muram_alloc() to s32 Rasmus Villemoes
2019-11-12  8:01   ` Qiang Zhao
2019-11-12  8:17     ` Rasmus Villemoes
2019-11-08 13:01 ` [PATCH v4 35/47] soc: fsl: qe: make cpm_muram_free() return void Rasmus Villemoes
2019-11-08 13:01 ` [PATCH v4 36/47] soc: fsl: qe: make cpm_muram_free() ignore a negative offset Rasmus Villemoes
2019-11-08 13:01 ` [PATCH v4 37/47] soc: fsl: qe: drop broken lazy call of cpm_muram_init() Rasmus Villemoes
2019-11-08 13:01 ` Rasmus Villemoes [this message]
2019-11-08 13:01 ` [PATCH v4 39/47] soc: fsl: qe: avoid IS_ERR_VALUE in ucc_slow.c Rasmus Villemoes
2019-11-08 13:01 ` [PATCH v4 40/47] soc: fsl: qe: drop use of IS_ERR_VALUE in qe_sdma_init() Rasmus Villemoes
2019-11-08 13:01 ` [PATCH v4 41/47] soc: fsl: qe: drop pointless check " Rasmus Villemoes
2019-11-08 13:01 ` [PATCH v4 42/47] soc: fsl: qe: avoid IS_ERR_VALUE in ucc_fast.c Rasmus Villemoes
2019-11-08 13:01 ` [PATCH v4 43/47] net/wan/fsl_ucc_hdlc: avoid use of IS_ERR_VALUE() Rasmus Villemoes
2019-11-08 13:01 ` [PATCH v4 44/47] net/wan/fsl_ucc_hdlc: fix reading of __be16 registers Rasmus Villemoes
2019-11-08 13:01 ` [PATCH v4 45/47] net/wan/fsl_ucc_hdlc: reject muram offsets above 64K Rasmus Villemoes
2019-11-15  4:41   ` Timur Tabi
2019-11-15  7:44     ` Rasmus Villemoes
2019-11-15 14:33       ` Timur Tabi
2019-11-08 13:01 ` [PATCH v4 46/47] net: ethernet: freescale: make UCC_GETH explicitly depend on PPC32 Rasmus Villemoes
2019-11-15  4:35   ` Timur Tabi
2019-11-15  5:44     ` Li Yang
2019-11-15  7:54       ` Rasmus Villemoes
2019-11-15 14:32         ` Timur Tabi
2019-11-15 14:31       ` Timur Tabi
2019-11-08 13:01 ` [PATCH v4 47/47] soc: fsl: qe: remove PPC32 dependency from CONFIG_QUICC_ENGINE Rasmus Villemoes
2019-11-08 23:48   ` Li Yang
2019-11-11  7:33     ` Rasmus Villemoes
2019-11-11 18:11       ` Li Yang
2019-11-13  2:48   ` Qiang Zhao
2019-11-20 19:42   ` kbuild test robot
2019-11-11 23:39 ` [PATCH v4 00/47] QUICC Engine support on ARM and ARM64 Li Yang
2019-11-12 20:45   ` Li Yang
2019-11-13  7:26     ` Rasmus Villemoes

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20191108130123.6839-39-linux@rasmusvillemoes.dk \
    --to=linux@rasmusvillemoes.dk \
    --cc=christophe.leroy@c-s.fr \
    --cc=leoyang.li@nxp.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=oss@buserror.net \
    --cc=qiang.zhao@nxp.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LinuxPPC-Dev Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linuxppc-dev/0 linuxppc-dev/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linuxppc-dev linuxppc-dev/ https://lore.kernel.org/linuxppc-dev \
		linuxppc-dev@lists.ozlabs.org linuxppc-dev@ozlabs.org
	public-inbox-index linuxppc-dev

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.ozlabs.lists.linuxppc-dev


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git