diff options
| author |   Steven Rostedt (Google) <rostedt@goodmis.org> | 2022-03-11 18:59:57 -0500 |
|---|---|---|
| committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2022-03-11 18:59:57 -0500 |
| commit | bc47ee4844d6b7d7351536cd99d35848c4449689 (patch) | |
| tree | 4e2f58ea38542874c6f7dac680a350ea600da358 /kernel/trace | |
| parent | tracing: Add snapshot at end of kernel boot up (diff) | |
| download | linux-dev-bc47ee4844d6b7d7351536cd99d35848c4449689.tar.xz linux-dev-bc47ee4844d6b7d7351536cd99d35848c4449689.zip | |
tracing/user_events: Use alloc_pages instead of kzalloc() for register pages
kzalloc virtual addresses do not work with SetPageReserved, use the actual
page virtual addresses instead via alloc_pages.
The issue is reported when booting with user_events and
DEBUG_VM_PGFLAGS=y.
Also make the number of events based on the ORDER.
Link: https://lore.kernel.org/all/CADYN=9+xY5Vku3Ws5E9S60SM5dCFfeGeRBkmDFbcxX0ZMoFing@mail.gmail.com/
Link: https://lore.kernel.org/all/20220311223028.1865-1-beaub@linux.microsoft.com/
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Reported-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/trace_events_user.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c index 4febc1d6ae72..e10ad057e797 100644 --- a/kernel/trace/trace_events_user.c +++ b/kernel/trace/trace_events_user.c @@ -30,9 +30,10 @@ /* * Limits how many trace_event calls user processes can create: - * Must be multiple of PAGE_SIZE. + * Must be a power of two of PAGE_SIZE. */ -#define MAX_PAGES 1 +#define MAX_PAGE_ORDER 0 +#define MAX_PAGES (1 << MAX_PAGE_ORDER) #define MAX_EVENTS (MAX_PAGES * PAGE_SIZE) /* Limit how long of an event name plus args within the subsystem. */ @@ -1622,16 +1623,17 @@ static void set_page_reservations(bool set) static int __init trace_events_user_init(void) { + struct page *pages; int ret; /* Zero all bits beside 0 (which is reserved for failures) */ bitmap_zero(page_bitmap, MAX_EVENTS); set_bit(0, page_bitmap); - register_page_data = kzalloc(MAX_EVENTS, GFP_KERNEL); - - if (!register_page_data) + pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, MAX_PAGE_ORDER); + if (!pages) return -ENOMEM; + register_page_data = page_address(pages); set_page_reservations(true); @@ -1640,7 +1642,7 @@ static int __init trace_events_user_init(void) if (ret) { pr_warn("user_events could not register with tracefs\n"); set_page_reservations(false); - kfree(register_page_data); + __free_pages(pages, MAX_PAGE_ORDER); return ret; } |