This is a note to let you know that I've just added the patch titled
intel_th: msu: Fix window switching without windows
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
intel_th-msu-fix-window-switching-without-windows.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 05b686b573cfb35a227c30787083a6631ff0f0c9 Mon Sep 17 00:00:00 2001
From: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Date: Tue, 17 Dec 2019 13:55:27 +0200
Subject: intel_th: msu: Fix window switching without windows
From: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
commit 05b686b573cfb35a227c30787083a6631ff0f0c9 upstream.
Commit 6cac7866c2741 ("intel_th: msu: Add a sysfs attribute to trigger
window switch") adds a NULL pointer dereference in the case when there are
no windows allocated:
> BUG: kernel NULL pointer dereference, address: 0000000000000000
> #PF: supervisor read access in kernel mode
> #PF: error_code(0x0000) - not-present page
> PGD 0 P4D 0
> Oops: 0000 1 SMP
> CPU: 5 PID: 1110 Comm: bash Not tainted 5.5.0-rc1+ #1
> RIP: 0010:msc_win_switch+0xa/0x80 [intel_th_msu]
> Call Trace:
> ? win_switch_store+0x9b/0xc0 [intel_th_msu]
> dev_attr_store+0x17/0x30
> sysfs_kf_write+0x3e/0x50
> kernfs_fop_write+0xda/0x1b0
> __vfs_write+0x1b/0x40
> vfs_write+0xb9/0x1a0
> ksys_write+0x67/0xe0
> __x64_sys_write+0x1a/0x20
> do_syscall_64+0x57/0x1d0
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fix that by disallowing window switching with multiwindow buffers without
windows.
Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Fixes: 6cac7866c274 ("intel_th: msu: Add a sysfs attribute to trigger window switch")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Reported-by: Ammy Yi <ammy.yi@xxxxxxxxx>
Tested-by: Ammy Yi <ammy.yi@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v5.2+
Link: https://lore.kernel.org/r/20191217115527.74383-5-alexander.shishkin@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/hwtracing/intel_th/msu.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
--- a/drivers/hwtracing/intel_th/msu.c
+++ b/drivers/hwtracing/intel_th/msu.c
@@ -1676,10 +1676,13 @@ static int intel_th_msc_init(struct msc
return 0;
}
-static void msc_win_switch(struct msc *msc)
+static int msc_win_switch(struct msc *msc)
{
struct msc_window *first;
+ if (list_empty(&msc->win_list))
+ return -EINVAL;
+
first = list_first_entry(&msc->win_list, struct msc_window, entry);
if (msc_is_last_win(msc->cur_win))
@@ -1691,6 +1694,8 @@ static void msc_win_switch(struct msc *m
msc->base_addr = msc_win_base_dma(msc->cur_win);
intel_th_trace_switch(msc->thdev);
+
+ return 0;
}
/**
@@ -2025,16 +2030,15 @@ win_switch_store(struct device *dev, str
if (val != 1)
return -EINVAL;
+ ret = -EINVAL;
mutex_lock(&msc->buf_mutex);
/*
* Window switch can only happen in the "multi" mode.
* If a external buffer is engaged, they have the full
* control over window switching.
*/
- if (msc->mode != MSC_MODE_MULTI || msc->mbuf)
- ret = -ENOTSUPP;
- else
- msc_win_switch(msc);
+ if (msc->mode == MSC_MODE_MULTI && !msc->mbuf)
+ ret = msc_win_switch(msc);
mutex_unlock(&msc->buf_mutex);
return ret ? ret : size;
Patches currently in stable-queue which might be from alexander.shishkin@xxxxxxxxxxxxxxx are
queue-5.4/perf-jevents-fix-resource-leak-in-process_mapfile-an.patch
queue-5.4/perf-tools-fix-cross-compile-for-arm64.patch
queue-5.4/perf-cs-etm-fix-definition-of-macro-to_cs_queue_nr.patch
queue-5.4/intel_th-pci-add-elkhart-lake-soc-support.patch
queue-5.4/intel_th-pci-add-comet-lake-pch-v-support.patch
queue-5.4/perf-report-add-warning-when-libunwind-not-compiled-.patch
queue-5.4/perf-vendor-events-arm64-fix-hisi-hip08-ddrc-pmu-eve.patch
queue-5.4/perf-session-fix-decompression-of-perf_record_compre.patch
queue-5.4/perf-test-avoid-infinite-loop-for-task-exit-case.patch
queue-5.4/perf-tests-disable-bp_signal-testing-for-arm64.patch
queue-5.4/perf-core-fix-the-mlock-accounting-again.patch
queue-5.4/perf-test-report-failure-for-mmap-events.patch
queue-5.4/perf-parse-fix-potential-memory-leak-when-handling-t.patch
queue-5.4/perf-tools-splice-events-onto-evlist-even-on-error.patch
queue-5.4/intel_th-msu-fix-window-switching-without-windows.patch
queue-5.4/perf-parse-if-pmu-configuration-fails-free-terms.patch
queue-5.4/intel_th-fix-freeing-irqs.patch
