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| author |   David Jander <david@protonic.nl> | 2022-06-09 14:13:34 +0200 |
|---|---|---|
| committer |   Mark Brown <broonie@kernel.org> | 2022-06-10 13:33:17 +0100 |
| commit | 67b9d64139e13621d3ab8bb0daad7602e5fe0778 (patch) | |
| tree | 54e97e2ca77f4dbb0ad881a8c74c0c3353aa3188 /drivers/spi/spi.c | |
| parent | spi: sifive: add PM callbacks to support suspend/resume (diff) | |
| download | linux-dev-67b9d64139e13621d3ab8bb0daad7602e5fe0778.tar.xz linux-dev-67b9d64139e13621d3ab8bb0daad7602e5fe0778.zip | |
spi: Fix per-cpu stats access on 32 bit systems
On 32 bit systems, the following kernel BUG is hit:
BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
caller is debug_smp_processor_id+0x18/0x24
CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.19.0-rc1-00001-g6ae0aec8a366 #181
Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
Backtrace:
dump_backtrace from show_stack+0x20/0x24
r7:81024ffd r6:00000000 r5:81024ffd r4:60000013
show_stack from dump_stack_lvl+0x60/0x78
dump_stack_lvl from dump_stack+0x14/0x1c
r7:81024ffd r6:80f652de r5:80bec180 r4:819a2500
dump_stack from check_preemption_disabled+0xc8/0xf0
check_preemption_disabled from debug_smp_processor_id+0x18/0x24
r8:8119b7e0 r7:81205534 r6:819f5c00 r5:819f4c00 r4:c083d724
debug_smp_processor_id from __spi_sync+0x78/0x220
__spi_sync from spi_sync+0x34/0x4c
r10:bb7bf4e0 r9:c083d724 r8:00000007 r7:81a068c0 r6:822a83c0 r5:c083d724
r4:819f4c00
spi_sync from spi_mem_exec_op+0x338/0x370
r5:000000b4 r4:c083d910
spi_mem_exec_op from spi_nor_read_id+0x98/0xdc
r10:bb7bf4e0 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:82358040
r4:819f7c40
spi_nor_read_id from spi_nor_detect+0x38/0x114
r7:82358040 r6:00000000 r5:819f7c40 r4:819f7c40
spi_nor_detect from spi_nor_scan+0x11c/0xbec
r10:bb7bf4e0 r9:00000000 r8:00000000 r7:c083da4c r6:00000000 r5:00010101
r4:819f7c40
spi_nor_scan from spi_nor_probe+0x10c/0x2d0
r10:bb7bf4e0 r9:bb7bf4d0 r8:00000000 r7:819f4c00 r6:00000000 r5:00000000
r4:819f7c40
per-cpu access needs to be guarded against preemption.
Fixes: 6598b91b5ac3 ("spi: spi.c: Convert statistics to per-cpu u64_stats_t")
Reported-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: David Jander <david@protonic.nl>
Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://lore.kernel.org/r/20220609121334.2984808-1-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi/spi.c')
| -rw-r--r-- | drivers/spi/spi.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index d94822bf3cec..ac61824b87b5 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -314,11 +314,13 @@ static void spi_statistics_add_transfer_stats(struct spi_statistics *pcpu_stats, struct spi_controller *ctlr) { int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1; - struct spi_statistics *stats = this_cpu_ptr(pcpu_stats); + struct spi_statistics *stats; if (l2len < 0) l2len = 0; + get_cpu(); + stats = this_cpu_ptr(pcpu_stats); u64_stats_update_begin(&stats->syncp); u64_stats_inc(&stats->transfers); @@ -333,6 +335,7 @@ static void spi_statistics_add_transfer_stats(struct spi_statistics *pcpu_stats, u64_stats_add(&stats->bytes_rx, xfer->len); u64_stats_update_end(&stats->syncp); + put_cpu(); } /* |