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For requests larger than KMALLOC_MAX_CACHE_SIZE, kmalloc us= es >> the page allocator and can only support up to KMALLOC_MAX_SIZE. For requ= est >> sizes bigger than KMALLOC_MAX_SIZE, the page allocator can emit a WARN >> because kmalloc allocates an order greater than MAX_PAGE_ORDER. Systems >> with panic_on_warn=3D1 crash because of this WARN. Fix it by rejecting a= ny >> kmalloc size bigger than KMALLOC_MAX_SIZE. >>=20 >> Fixes: aadb4bc4a1f9 ("SLUB: direct pass through of page size or higher k= malloc requests") >> Reported-by: syzbot+805630f1453e490427fa@syzkaller.appspotmail.com >> Closes: https://lore.kernel.org/all/6a820ebc.9ebadd4d.20b15e.001b.GAE@go= ogle.com/ >> Tested-by: syzbot+805630f1453e490427fa@syzkaller.appspotmail.com >> Signed-off-by: Zi Yan >> Cc: stable@vger.kernel.org >> --- >> It fixes a page allocator warning (order > MAX_PAGE_ORDER) when gadgetfs >> requests excessively large memory from kmalloc. Instead of adding >> __GFP_NOWARN to suppress the warning, as was done for usbfs[1], change >> kmalloc to return NULL without a warning for this specific issue. >>=20 >> [1] commit 4f2629ea67e72 ("USB: usbfs: Don't WARN about excessively larg= e memory allocations") > > Thanks for doing this. If you like, I can write a follow-up patch to=20 > remove the __GFP_NOWARN added in 4f2629ea67e72, now that it isn't needed= =20 > any more. Sure. Once the patch gets an Ack or Rb from a maintainer and Andrew picks it up, feel free to send a cleanup patch. Thanks. --=20 Best Regards, Yan, Zi