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authorMathieu Poirier <mathieu.poirier@linaro.org>2018-07-16 17:13:51 -0600
committerIngo Molnar <mingo@kernel.org>2018-07-25 11:46:22 +0200
commit7f635ff187ab6be0b350b3ec06791e376af238ab (patch)
treebb6645c4ea8d8188f238656414003226b573e5b2
parent6cbc304f2f360f25cc8607817239d6f4a2fd3dc5 (diff)
download96b-common-7f635ff187ab6be0b350b3ec06791e376af238ab.tar.gz
perf/core: Fix crash when using HW tracing kernel filters
In function perf_event_parse_addr_filter(), the path::dentry of each struct perf_addr_filter is left unassigned (as it should be) when the pattern being parsed is related to kernel space. But in function perf_addr_filter_match() the same dentries are given to d_inode() where the value is not expected to be NULL, resulting in the following splat: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000058 pc : perf_event_mmap+0x2fc/0x5a0 lr : perf_event_mmap+0x2c8/0x5a0 Process uname (pid: 2860, stack limit = 0x000000001cbcca37) Call trace: perf_event_mmap+0x2fc/0x5a0 mmap_region+0x124/0x570 do_mmap+0x344/0x4f8 vm_mmap_pgoff+0xe4/0x110 vm_mmap+0x2c/0x40 elf_map+0x60/0x108 load_elf_binary+0x450/0x12c4 search_binary_handler+0x90/0x290 __do_execve_file.isra.13+0x6e4/0x858 sys_execve+0x3c/0x50 el0_svc_naked+0x30/0x34 This patch is fixing the problem by introducing a new check in function perf_addr_filter_match() to see if the filter's dentry is NULL. Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: acme@kernel.org Cc: miklos@szeredi.hu Cc: namhyung@kernel.org Cc: songliubraving@fb.com Fixes: 9511bce9fe8e ("perf/core: Fix bad use of igrab()") Link: http://lkml.kernel.org/r/1531782831-1186-1-git-send-email-mathieu.poirier@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--kernel/events/core.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index cdb32cf8e33c..eec2d5fb676b 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7337,6 +7337,10 @@ static bool perf_addr_filter_match(struct perf_addr_filter *filter,
struct file *file, unsigned long offset,
unsigned long size)
{
+ /* d_inode(NULL) won't be equal to any mapped user-space file */
+ if (!filter->path.dentry)
+ return false;
+
if (d_inode(filter->path.dentry) != file_inode(file))
return false;