diff options
| author | Thomas Nixon <tom@tomn.co.uk> | 2023-03-26 10:19:21 +0000 |
|---|---|---|
| committer | Hauke Mehrtens <hauke@hauke-m.de> | 2023-04-02 22:07:26 +0200 |
| commit | 354ad1084a074392e72d61e68e9bdbf16b4b774b (patch) | |
| tree | 2e7381ca2e6d90296e372cab6eb9d19534ea90c0 | |
| parent | 6035401f46461bcbe4f0a78d6a751f9ae09557ae (diff) | |
| download | openwrt-354ad1084a074392e72d61e68e9bdbf16b4b774b.tar.gz openwrt-354ad1084a074392e72d61e68e9bdbf16b4b774b.tar.bz2 openwrt-354ad1084a074392e72d61e68e9bdbf16b4b774b.zip | |
lantiq: nand: don't yield while holding spinlock
The nand driver normally while waiting for the device to become ready;
this is normally fine, but xway_nand holds the ebu_lock spinlock, and
this can cause lockups if other threads which use ebu_lock are
interleaved. Fix this by waiting instead of polling.
This mainly showed up as crashes in ath9k_pci_owl_loader (see
https://github.com/openwrt/openwrt/issues/9829 ), but turning on
spinlock debugging shows this happening in other places too.
This doesn't seem to measurably impact boot time.
Tested on bt_homehub-v5a with 5.10 and 5.15.
Signed-off-by: Thomas Nixon <tom@tomn.co.uk>
[Add commit description into patch]
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
(cherry picked from commit d3b47909b199b876f67a0387b5545cb73bd6b815)
| -rw-r--r-- | target/linux/lantiq/patches-5.10/0400-mtd-rawnand-xway-don-t-yield-while-holding-spinlock.patch | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/target/linux/lantiq/patches-5.10/0400-mtd-rawnand-xway-don-t-yield-while-holding-spinlock.patch b/target/linux/lantiq/patches-5.10/0400-mtd-rawnand-xway-don-t-yield-while-holding-spinlock.patch new file mode 100644 index 0000000000..edf0626860 --- /dev/null +++ b/target/linux/lantiq/patches-5.10/0400-mtd-rawnand-xway-don-t-yield-while-holding-spinlock.patch @@ -0,0 +1,38 @@ +From 416f25a948d11ef15733f2e31658d31b5cc7bef6 Mon Sep 17 00:00:00 2001 +From: Thomas Nixon <tom@tomn.co.uk> +Date: Sun, 26 Mar 2023 11:08:49 +0100 +Subject: [PATCH] mtd: rawnand: xway: don't yield while holding spinlock + +The nand driver normally while waiting for the device to become ready; +this is normally fine, but xway_nand holds the ebu_lock spinlock, and +this can cause lockups if other threads which use ebu_lock are +interleaved. Fix this by waiting instead of polling. + +This mainly showed up as crashes in ath9k_pci_owl_loader (see +https://github.com/openwrt/openwrt/issues/9829 ), but turning on +spinlock debugging shows this happening in other places too. + +This doesn't seem to measurably impact boot time. + +Signed-off-by: Thomas Nixon <tom@tomn.co.uk> +--- + drivers/mtd/nand/raw/xway_nand.c | 8 +++++++- + 1 file changed, 7 insertions(+), 1 deletion(-) + +--- a/drivers/mtd/nand/raw/xway_nand.c ++++ b/drivers/mtd/nand/raw/xway_nand.c +@@ -175,7 +175,13 @@ static void xway_cmd_ctrl(struct nand_ch + + static int xway_dev_ready(struct nand_chip *chip) + { +- return ltq_ebu_r32(EBU_NAND_WAIT) & NAND_WAIT_RD; ++ /* ++ * wait until ready, as otherwise the driver will yield in nand_wait or ++ * nand_wait_ready, which is a bad idea when we're holding ebu_lock ++ */ ++ while ((ltq_ebu_r32(EBU_NAND_WAIT) & NAND_WAIT_RD) == 0) ++ cpu_relax(); ++ return 1; + } + + static unsigned char xway_read_byte(struct nand_chip *chip) |