| Message ID | 20220609121334.2984808-1-david@protonic.nl (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 67b9d64139e13621d3ab8bb0daad7602e5fe0778 |
| Headers | show |
| Series | spi: Fix per-cpu stats access on 32 bit systems | expand |
On Thu, Jun 09, 2022 at 02:13:34PM +0200, David Jander wrote: > 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> Hi, the issue isn't 32-bit specific. I'm seeing it on an aarch64 machine (mt8192-asurada-spherion) running next-20220609. The fix did work for me, so Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com> Thanks! Nícolas
On Thu, Jun 9, 2022 at 2:29 PM David Jander <david@protonic.nl> wrote: > > On 32 bit systems, the following kernel BUG is hit: > > BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1 https://www.kernel.org/doc/html/latest/process/submitting-patches.html#backtraces-in-commit-mesages
On Thu, 9 Jun 2022 14:13:34 +0200, David Jander wrote: > 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 > > [...] Applied to https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next Thanks! [1/1] spi: Fix per-cpu stats access on 32 bit systems commit: 67b9d64139e13621d3ab8bb0daad7602e5fe0778 All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted. You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed. If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced. Please add any relevant lists and maintainers to the CCs when replying to this mail. Thanks, Mark
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(); } /* diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 2e63b4935deb..c96f526d9a20 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -84,18 +84,24 @@ struct spi_statistics { #define SPI_STATISTICS_ADD_TO_FIELD(pcpu_stats, field, count) \ do { \ - struct spi_statistics *__lstats = this_cpu_ptr(pcpu_stats); \ + struct spi_statistics *__lstats; \ + get_cpu(); \ + __lstats = this_cpu_ptr(pcpu_stats); \ u64_stats_update_begin(&__lstats->syncp); \ u64_stats_add(&__lstats->field, count); \ u64_stats_update_end(&__lstats->syncp); \ + put_cpu(); \ } while (0) #define SPI_STATISTICS_INCREMENT_FIELD(pcpu_stats, field) \ do { \ - struct spi_statistics *__lstats = this_cpu_ptr(pcpu_stats); \ + struct spi_statistics *__lstats; \ + get_cpu(); \ + __lstats = this_cpu_ptr(pcpu_stats); \ u64_stats_update_begin(&__lstats->syncp); \ u64_stats_inc(&__lstats->field); \ u64_stats_update_end(&__lstats->syncp); \ + put_cpu(); \ } while (0) /**
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> --- drivers/spi/spi.c | 5 ++++- include/linux/spi/spi.h | 10 ++++++++-- 2 files changed, 12 insertions(+), 3 deletions(-)